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UBI: simplify PEB protection code 

UBI has 2 RB-trees to implement PEB protection, which is too
much for simply prevent PEB from being moved for some time.
This patch implements this using lists. The benefits:

1. No need to allocate protection entry on each PEB get.
2. No need to maintain balanced trees and walk them.

Signed-off-by: Xiaochuan-Xu <xiaochuan-xu@cqu.edu.cn>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
This commit is contained in:
Xiaochuan-Xu 2008-12-15 21:07:41 +08:00 committed by Artem Bityutskiy
parent 23553b2c08
commit 7b6c32daec
2 changed files with 163 additions and 242 deletions
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39
drivers/mtd/ubi/ubi.h
View File

@ -73,6 +73,13 @@
*/ */
#define UBI_IO_RETRIES 3 #define UBI_IO_RETRIES 3
/*
* Length of the protection queue. The length is effectively equivalent to the
* number of (global) erase cycles PEBs are protected from the wear-leveling
* worker.
*/
#define UBI_PROT_QUEUE_LEN 10
/* /*
* Error codes returned by the I/O sub-system. * Error codes returned by the I/O sub-system.
* *
@ -96,6 +103,7 @@ enum {
/** /**
* struct ubi_wl_entry - wear-leveling entry. * struct ubi_wl_entry - wear-leveling entry.
* @u.rb: link in the corresponding (free/used) RB-tree * @u.rb: link in the corresponding (free/used) RB-tree
* @u.list: link in the protection queue
* @ec: erase counter * @ec: erase counter
* @pnum: physical eraseblock number * @pnum: physical eraseblock number
* *
@ -106,6 +114,7 @@ enum {
struct ubi_wl_entry { struct ubi_wl_entry {
union { union {
struct rb_node rb; struct rb_node rb;
struct list_head list;
} u; } u;
int ec; int ec;
int pnum; int pnum;
@ -290,7 +299,7 @@ struct ubi_wl_entry;
* @beb_rsvd_level: normal level of PEBs reserved for bad PEB handling * @beb_rsvd_level: normal level of PEBs reserved for bad PEB handling
* *
* @autoresize_vol_id: ID of the volume which has to be auto-resized at the end * @autoresize_vol_id: ID of the volume which has to be auto-resized at the end
* of UBI ititializetion * of UBI initialization
* @vtbl_slots: how many slots are available in the volume table * @vtbl_slots: how many slots are available in the volume table
* @vtbl_size: size of the volume table in bytes * @vtbl_size: size of the volume table in bytes
* @vtbl: in-RAM volume table copy * @vtbl: in-RAM volume table copy
@ -308,18 +317,17 @@ struct ubi_wl_entry;
* @used: RB-tree of used physical eraseblocks * @used: RB-tree of used physical eraseblocks
* @free: RB-tree of free physical eraseblocks * @free: RB-tree of free physical eraseblocks
* @scrub: RB-tree of physical eraseblocks which need scrubbing * @scrub: RB-tree of physical eraseblocks which need scrubbing
* @prot: protection trees * @pq: protection queue (contain physical eraseblocks which are temporarily
* @prot.pnum: protection tree indexed by physical eraseblock numbers * protected from the wear-leveling worker)
* @prot.aec: protection tree indexed by absolute erase counter value * @pq_head: protection queue head
* @wl_lock: protects the @used, @free, @prot, @lookuptbl, @abs_ec, @move_from, * @wl_lock: protects the @used, @free, @pq, @pq_head, @lookuptbl, @move_from,
* @move_to, @move_to_put @erase_pending, @wl_scheduled, and @works * @move_to, @move_to_put @erase_pending, @wl_scheduled and @works
* fields * fields
* @move_mutex: serializes eraseblock moves * @move_mutex: serializes eraseblock moves
* @work_sem: sycnhronizes the WL worker with use tasks * @work_sem: synchronizes the WL worker with use tasks
* @wl_scheduled: non-zero if the wear-leveling was scheduled * @wl_scheduled: non-zero if the wear-leveling was scheduled
* @lookuptbl: a table to quickly find a &struct ubi_wl_entry object for any * @lookuptbl: a table to quickly find a &struct ubi_wl_entry object for any
* physical eraseblock * physical eraseblock
* @abs_ec: absolute erase counter
* @move_from: physical eraseblock from where the data is being moved * @move_from: physical eraseblock from where the data is being moved
* @move_to: physical eraseblock where the data is being moved to * @move_to: physical eraseblock where the data is being moved to
* @move_to_put: if the "to" PEB was put * @move_to_put: if the "to" PEB was put
@ -353,11 +361,11 @@ struct ubi_wl_entry;
* *
* @peb_buf1: a buffer of PEB size used for different purposes * @peb_buf1: a buffer of PEB size used for different purposes
* @peb_buf2: another buffer of PEB size used for different purposes * @peb_buf2: another buffer of PEB size used for different purposes
* @buf_mutex: proptects @peb_buf1 and @peb_buf2 * @buf_mutex: protects @peb_buf1 and @peb_buf2
* @ckvol_mutex: serializes static volume checking when opening * @ckvol_mutex: serializes static volume checking when opening
* @mult_mutex: serializes operations on multiple volumes, like re-nameing * @mult_mutex: serializes operations on multiple volumes, like re-naming
* @dbg_peb_buf: buffer of PEB size used for debugging * @dbg_peb_buf: buffer of PEB size used for debugging
* @dbg_buf_mutex: proptects @dbg_peb_buf * @dbg_buf_mutex: protects @dbg_peb_buf
*/ */
struct ubi_device { struct ubi_device {
struct cdev cdev; struct cdev cdev;
@ -394,16 +402,13 @@ struct ubi_device {
struct rb_root used; struct rb_root used;
struct rb_root free; struct rb_root free;
struct rb_root scrub; struct rb_root scrub;
struct { struct list_head pq[UBI_PROT_QUEUE_LEN];
struct rb_root pnum; int pq_head;
struct rb_root aec;
} prot;
spinlock_t wl_lock; spinlock_t wl_lock;
struct mutex move_mutex; struct mutex move_mutex;
struct rw_semaphore work_sem; struct rw_semaphore work_sem;
int wl_scheduled; int wl_scheduled;
struct ubi_wl_entry **lookuptbl; struct ubi_wl_entry **lookuptbl;
unsigned long long abs_ec;
struct ubi_wl_entry *move_from; struct ubi_wl_entry *move_from;
struct ubi_wl_entry *move_to; struct ubi_wl_entry *move_to;
int move_to_put; int move_to_put;

366
drivers/mtd/ubi/wl.c
View File

@ -22,7 +22,7 @@
* UBI wear-leveling sub-system. * UBI wear-leveling sub-system.
* *
* This sub-system is responsible for wear-leveling. It works in terms of * This sub-system is responsible for wear-leveling. It works in terms of
* physical* eraseblocks and erase counters and knows nothing about logical * physical eraseblocks and erase counters and knows nothing about logical
* eraseblocks, volumes, etc. From this sub-system's perspective all physical * eraseblocks, volumes, etc. From this sub-system's perspective all physical
* eraseblocks are of two types - used and free. Used physical eraseblocks are * eraseblocks are of two types - used and free. Used physical eraseblocks are
* those that were "get" by the 'ubi_wl_get_peb()' function, and free physical * those that were "get" by the 'ubi_wl_get_peb()' function, and free physical
@ -55,8 +55,39 @@
* *
* As it was said, for the UBI sub-system all physical eraseblocks are either * As it was said, for the UBI sub-system all physical eraseblocks are either
* "free" or "used". Free eraseblock are kept in the @wl->free RB-tree, while * "free" or "used". Free eraseblock are kept in the @wl->free RB-tree, while
* used eraseblocks are kept in a set of different RB-trees: @wl->used, * used eraseblocks are kept in @wl->used or @wl->scrub RB-trees, or
* @wl->prot.pnum, @wl->prot.aec, and @wl->scrub. * (temporarily) in the @wl->pq queue.
*
* When the WL sub-system returns a physical eraseblock, the physical
* eraseblock is protected from being moved for some "time". For this reason,
* the physical eraseblock is not directly moved from the @wl->free tree to the
* @wl->used tree. There is a protection queue in between where this
* physical eraseblock is temporarily stored (@wl->pq).
*
* All this protection stuff is needed because:
* o we don't want to move physical eraseblocks just after we have given them
* to the user; instead, we first want to let users fill them up with data;
*
* o there is a chance that the user will put the physical eraseblock very
* soon, so it makes sense not to move it for some time, but wait; this is
* especially important in case of "short term" physical eraseblocks.
*
* Physical eraseblocks stay protected only for limited time. But the "time" is
* measured in erase cycles in this case. This is implemented with help of the
* protection queue. Eraseblocks are put to the tail of this queue when they
* are returned by the 'ubi_wl_get_peb()', and eraseblocks are removed from the
* head of the queue on each erase operation (for any eraseblock). So the
* length of the queue defines how may (global) erase cycles PEBs are protected.
*
* To put it differently, each physical eraseblock has 2 main states: free and
* used. The former state corresponds to the @wl->free tree. The latter state
* is split up on several sub-states:
* o the WL movement is allowed (@wl->used tree);
* o the WL movement is temporarily prohibited (@wl->pq queue);
* o scrubbing is needed (@wl->scrub tree).
*
* Depending on the sub-state, wear-leveling entries of the used physical
* eraseblocks may be kept in one of those structures.
* *
* Note, in this implementation, we keep a small in-RAM object for each physical * Note, in this implementation, we keep a small in-RAM object for each physical
* eraseblock. This is surely not a scalable solution. But it appears to be good * eraseblock. This is surely not a scalable solution. But it appears to be good
@ -70,9 +101,6 @@
* target PEB, we pick a PEB with the highest EC if our PEB is "old" and we * target PEB, we pick a PEB with the highest EC if our PEB is "old" and we
* pick target PEB with an average EC if our PEB is not very "old". This is a * pick target PEB with an average EC if our PEB is not very "old". This is a
* room for future re-works of the WL sub-system. * room for future re-works of the WL sub-system.
*
* Note: the stuff with protection trees looks too complex and is difficult to
* understand. Should be fixed.
*/ */
#include <linux/slab.h> #include <linux/slab.h>
@ -84,14 +112,6 @@
/* Number of physical eraseblocks reserved for wear-leveling purposes */ /* Number of physical eraseblocks reserved for wear-leveling purposes */
#define WL_RESERVED_PEBS 1 #define WL_RESERVED_PEBS 1
/*
* How many erase cycles are short term, unknown, and long term physical
* eraseblocks protected.
*/
#define ST_PROTECTION 16
#define U_PROTECTION 10
#define LT_PROTECTION 4
/* /*
* Maximum difference between two erase counters. If this threshold is * Maximum difference between two erase counters. If this threshold is
* exceeded, the WL sub-system starts moving data from used physical * exceeded, the WL sub-system starts moving data from used physical
@ -119,65 +139,10 @@
*/ */
#define WL_MAX_FAILURES 32 #define WL_MAX_FAILURES 32
/**
* struct ubi_wl_prot_entry - PEB protection entry.
* @rb_pnum: link in the @wl->prot.pnum RB-tree
* @rb_aec: link in the @wl->prot.aec RB-tree
* @abs_ec: the absolute erase counter value when the protection ends
* @e: the wear-leveling entry of the physical eraseblock under protection
*
* When the WL sub-system returns a physical eraseblock, the physical
* eraseblock is protected from being moved for some "time". For this reason,
* the physical eraseblock is not directly moved from the @wl->free tree to the
* @wl->used tree. There is one more tree in between where this physical
* eraseblock is temporarily stored (@wl->prot).
*
* All this protection stuff is needed because:
* o we don't want to move physical eraseblocks just after we have given them
* to the user; instead, we first want to let users fill them up with data;
*
* o there is a chance that the user will put the physical eraseblock very
* soon, so it makes sense not to move it for some time, but wait; this is
* especially important in case of "short term" physical eraseblocks.
*
* Physical eraseblocks stay protected only for limited time. But the "time" is
* measured in erase cycles in this case. This is implemented with help of the
* absolute erase counter (@wl->abs_ec). When it reaches certain value, the
* physical eraseblocks are moved from the protection trees (@wl->prot.*) to
* the @wl->used tree.
*
* Protected physical eraseblocks are searched by physical eraseblock number
* (when they are put) and by the absolute erase counter (to check if it is
* time to move them to the @wl->used tree). So there are actually 2 RB-trees
* storing the protected physical eraseblocks: @wl->prot.pnum and
* @wl->prot.aec. They are referred to as the "protection" trees. The
* first one is indexed by the physical eraseblock number. The second one is
* indexed by the absolute erase counter. Both trees store
* &struct ubi_wl_prot_entry objects.
*
* Each physical eraseblock has 2 main states: free and used. The former state
* corresponds to the @wl->free tree. The latter state is split up on several
* sub-states:
* o the WL movement is allowed (@wl->used tree);
* o the WL movement is temporarily prohibited (@wl->prot.pnum and
* @wl->prot.aec trees);
* o scrubbing is needed (@wl->scrub tree).
*
* Depending on the sub-state, wear-leveling entries of the used physical
* eraseblocks may be kept in one of those trees.
*/
struct ubi_wl_prot_entry {
struct rb_node rb_pnum;
struct rb_node rb_aec;
unsigned long long abs_ec;
struct ubi_wl_entry *e;
};
/** /**
* struct ubi_work - UBI work description data structure. * struct ubi_work - UBI work description data structure.
* @list: a link in the list of pending works * @list: a link in the list of pending works
* @func: worker function * @func: worker function
* @priv: private data of the worker function
* @e: physical eraseblock to erase * @e: physical eraseblock to erase
* @torture: if the physical eraseblock has to be tortured * @torture: if the physical eraseblock has to be tortured
* *
@ -198,9 +163,11 @@ struct ubi_work {
static int paranoid_check_ec(struct ubi_device *ubi, int pnum, int ec); static int paranoid_check_ec(struct ubi_device *ubi, int pnum, int ec);
static int paranoid_check_in_wl_tree(struct ubi_wl_entry *e, static int paranoid_check_in_wl_tree(struct ubi_wl_entry *e,
struct rb_root *root); struct rb_root *root);
static int paranoid_check_in_pq(struct ubi_device *ubi, struct ubi_wl_entry *e);
#else #else
#define paranoid_check_ec(ubi, pnum, ec) 0 #define paranoid_check_ec(ubi, pnum, ec) 0
#define paranoid_check_in_wl_tree(e, root) #define paranoid_check_in_wl_tree(e, root)
#define paranoid_check_in_pq(ubi, e) 0
#endif #endif
/** /**
@ -355,49 +322,24 @@ static int in_wl_tree(struct ubi_wl_entry *e, struct rb_root *root)
} }
/** /**
* prot_tree_add - add physical eraseblock to protection trees. * prot_queue_add - add physical eraseblock to the protection queue.
* @ubi: UBI device description object * @ubi: UBI device description object
* @e: the physical eraseblock to add * @e: the physical eraseblock to add
* @pe: protection entry object to use
* @ec: for how many erase operations this PEB should be protected
* *
* @wl->lock has to be locked. * This function adds @e to the tail of the protection queue @ubi->pq, where
* @e will stay for %UBI_PROT_QUEUE_LEN erase operations and will be
* temporarily protected from the wear-leveling worker. Note, @wl->lock has to
* be locked.
*/ */
static void prot_tree_add(struct ubi_device *ubi, struct ubi_wl_entry *e, static void prot_queue_add(struct ubi_device *ubi, struct ubi_wl_entry *e)
struct ubi_wl_prot_entry *pe, int ec)
{ {
struct rb_node **p, *parent = NULL; int pq_tail = ubi->pq_head - 1;
struct ubi_wl_prot_entry *pe1;
pe->e = e; if (pq_tail < 0)
pe->abs_ec = ubi->abs_ec + ec; pq_tail = UBI_PROT_QUEUE_LEN - 1;
ubi_assert(pq_tail >= 0 && pq_tail < UBI_PROT_QUEUE_LEN);
p = &ubi->prot.pnum.rb_node; list_add_tail(&e->u.list, &ubi->pq[pq_tail]);
while (*p) { dbg_wl("added PEB %d EC %d to the protection queue", e->pnum, e->ec);
parent = *p;
pe1 = rb_entry(parent, struct ubi_wl_prot_entry, rb_pnum);
if (e->pnum < pe1->e->pnum)
p = &(*p)->rb_left;
else
p = &(*p)->rb_right;
}
rb_link_node(&pe->rb_pnum, parent, p);
rb_insert_color(&pe->rb_pnum, &ubi->prot.pnum);
p = &ubi->prot.aec.rb_node;
parent = NULL;
while (*p) {
parent = *p;
pe1 = rb_entry(parent, struct ubi_wl_prot_entry, rb_aec);
if (pe->abs_ec < pe1->abs_ec)
p = &(*p)->rb_left;
else
p = &(*p)->rb_right;
}
rb_link_node(&pe->rb_aec, parent, p);
rb_insert_color(&pe->rb_aec, &ubi->prot.aec);
} }
/** /**
@ -442,17 +384,12 @@ static struct ubi_wl_entry *find_wl_entry(struct rb_root *root, int max)
*/ */
int ubi_wl_get_peb(struct ubi_device *ubi, int dtype) int ubi_wl_get_peb(struct ubi_device *ubi, int dtype)
{ {
int err, protect, medium_ec; int err, medium_ec;
struct ubi_wl_entry *e, *first, *last; struct ubi_wl_entry *e, *first, *last;
struct ubi_wl_prot_entry *pe;
ubi_assert(dtype == UBI_LONGTERM || dtype == UBI_SHORTTERM || ubi_assert(dtype == UBI_LONGTERM || dtype == UBI_SHORTTERM ||
dtype == UBI_UNKNOWN); dtype == UBI_UNKNOWN);
pe = kmalloc(sizeof(struct ubi_wl_prot_entry), GFP_NOFS);
if (!pe)
return -ENOMEM;
retry: retry:
spin_lock(&ubi->wl_lock); spin_lock(&ubi->wl_lock);
if (!ubi->free.rb_node) { if (!ubi->free.rb_node) {
@ -460,16 +397,13 @@ int ubi_wl_get_peb(struct ubi_device *ubi, int dtype)
ubi_assert(list_empty(&ubi->works)); ubi_assert(list_empty(&ubi->works));
ubi_err("no free eraseblocks"); ubi_err("no free eraseblocks");
spin_unlock(&ubi->wl_lock); spin_unlock(&ubi->wl_lock);
kfree(pe);
return -ENOSPC; return -ENOSPC;
} }
spin_unlock(&ubi->wl_lock); spin_unlock(&ubi->wl_lock);
err = produce_free_peb(ubi); err = produce_free_peb(ubi);
if (err < 0) { if (err < 0)
kfree(pe);
return err; return err;
}
goto retry; goto retry;
} }
@ -482,7 +416,6 @@ int ubi_wl_get_peb(struct ubi_device *ubi, int dtype)
* %WL_FREE_MAX_DIFF. * %WL_FREE_MAX_DIFF.
*/ */
e = find_wl_entry(&ubi->free, WL_FREE_MAX_DIFF); e = find_wl_entry(&ubi->free, WL_FREE_MAX_DIFF);
protect = LT_PROTECTION;
break; break;
case UBI_UNKNOWN: case UBI_UNKNOWN:
/* /*
@ -502,7 +435,6 @@ int ubi_wl_get_peb(struct ubi_device *ubi, int dtype)
medium_ec = (first->ec + WL_FREE_MAX_DIFF)/2; medium_ec = (first->ec + WL_FREE_MAX_DIFF)/2;
e = find_wl_entry(&ubi->free, medium_ec); e = find_wl_entry(&ubi->free, medium_ec);
} }
protect = U_PROTECTION;
break; break;
case UBI_SHORTTERM: case UBI_SHORTTERM:
/* /*
@ -510,63 +442,45 @@ int ubi_wl_get_peb(struct ubi_device *ubi, int dtype)
* lowest erase counter as we expect it will be erased soon. * lowest erase counter as we expect it will be erased soon.
*/ */
e = rb_entry(rb_first(&ubi->free), struct ubi_wl_entry, u.rb); e = rb_entry(rb_first(&ubi->free), struct ubi_wl_entry, u.rb);
protect = ST_PROTECTION;
break; break;
default: default:
protect = 0;
e = NULL;
BUG(); BUG();
} }
paranoid_check_in_wl_tree(e, &ubi->free);
/* /*
* Move the physical eraseblock to the protection trees where it will * Move the physical eraseblock to the protection queue where it will
* be protected from being moved for some time. * be protected from being moved for some time.
*/ */
paranoid_check_in_wl_tree(e, &ubi->free);
rb_erase(&e->u.rb, &ubi->free); rb_erase(&e->u.rb, &ubi->free);
prot_tree_add(ubi, e, pe, protect); dbg_wl("PEB %d EC %d", e->pnum, e->ec);
prot_queue_add(ubi, e);
dbg_wl("PEB %d EC %d, protection %d", e->pnum, e->ec, protect);
spin_unlock(&ubi->wl_lock); spin_unlock(&ubi->wl_lock);
return e->pnum; return e->pnum;
} }
/** /**
* prot_tree_del - remove a physical eraseblock from the protection trees * prot_queue_del - remove a physical eraseblock from the protection queue.
* @ubi: UBI device description object * @ubi: UBI device description object
* @pnum: the physical eraseblock to remove * @pnum: the physical eraseblock to remove
* *
* This function returns PEB @pnum from the protection trees and returns zero * This function deletes PEB @pnum from the protection queue and returns zero
* in case of success and %-ENODEV if the PEB was not found in the protection * in case of success and %-ENODEV if the PEB was not found.
* trees.
*/ */
static int prot_tree_del(struct ubi_device *ubi, int pnum) static int prot_queue_del(struct ubi_device *ubi, int pnum)
{ {
struct rb_node *p; struct ubi_wl_entry *e;
struct ubi_wl_prot_entry *pe = NULL;
p = ubi->prot.pnum.rb_node; e = ubi->lookuptbl[pnum];
while (p) { if (!e)
return -ENODEV;
pe = rb_entry(p, struct ubi_wl_prot_entry, rb_pnum); if (paranoid_check_in_pq(ubi, e))
return -ENODEV;
if (pnum == pe->e->pnum) list_del(&e->u.list);
goto found; dbg_wl("deleted PEB %d from the protection queue", e->pnum);
if (pnum < pe->e->pnum)
p = p->rb_left;
else
p = p->rb_right;
}
return -ENODEV;
found:
ubi_assert(pe->e->pnum == pnum);
rb_erase(&pe->rb_aec, &ubi->prot.aec);
rb_erase(&pe->rb_pnum, &ubi->prot.pnum);
kfree(pe);
return 0; return 0;
} }
@ -632,47 +546,47 @@ static int sync_erase(struct ubi_device *ubi, struct ubi_wl_entry *e,
} }
/** /**
* check_protection_over - check if it is time to stop protecting some PEBs. * serve_prot_queue - check if it is time to stop protecting PEBs.
* @ubi: UBI device description object * @ubi: UBI device description object
* *
* This function is called after each erase operation, when the absolute erase * This function is called after each erase operation and removes PEBs from the
* counter is incremented, to check if some physical eraseblock have not to be * tail of the protection queue. These PEBs have been protected for long enough
* protected any longer. These physical eraseblocks are moved from the * and should be moved to the used tree.
* protection trees to the used tree.
*/ */
static void check_protection_over(struct ubi_device *ubi) static void serve_prot_queue(struct ubi_device *ubi)
{ {
struct ubi_wl_prot_entry *pe; struct ubi_wl_entry *e, *tmp;
int count;
/* /*
* There may be several protected physical eraseblock to remove, * There may be several protected physical eraseblock to remove,
* process them all. * process them all.
*/ */
while (1) { repeat:
spin_lock(&ubi->wl_lock); count = 0;
if (!ubi->prot.aec.rb_node) { spin_lock(&ubi->wl_lock);
list_for_each_entry_safe(e, tmp, &ubi->pq[ubi->pq_head], u.list) {
dbg_wl("PEB %d EC %d protection over, move to used tree",
e->pnum, e->ec);
list_del(&e->u.list);
wl_tree_add(e, &ubi->used);
if (count++ > 32) {
/*
* Let's be nice and avoid holding the spinlock for
* too long.
*/
spin_unlock(&ubi->wl_lock); spin_unlock(&ubi->wl_lock);
break; cond_resched();
goto repeat;
} }
pe = rb_entry(rb_first(&ubi->prot.aec),
struct ubi_wl_prot_entry, rb_aec);
if (pe->abs_ec > ubi->abs_ec) {
spin_unlock(&ubi->wl_lock);
break;
}
dbg_wl("PEB %d protection over, abs_ec %llu, PEB abs_ec %llu",
pe->e->pnum, ubi->abs_ec, pe->abs_ec);
rb_erase(&pe->rb_aec, &ubi->prot.aec);
rb_erase(&pe->rb_pnum, &ubi->prot.pnum);
wl_tree_add(pe->e, &ubi->used);
spin_unlock(&ubi->wl_lock);
kfree(pe);
cond_resched();
} }
ubi->pq_head += 1;
if (ubi->pq_head == UBI_PROT_QUEUE_LEN)
ubi->pq_head = 0;
ubi_assert(ubi->pq_head >= 0 && ubi->pq_head < UBI_PROT_QUEUE_LEN);
spin_unlock(&ubi->wl_lock);
} }
/** /**
@ -680,8 +594,8 @@ static void check_protection_over(struct ubi_device *ubi)
* @ubi: UBI device description object * @ubi: UBI device description object
* @wrk: the work to schedule * @wrk: the work to schedule
* *
* This function enqueues a work defined by @wrk to the tail of the pending * This function adds a work defined by @wrk to the tail of the pending works
* works list. * list.
*/ */
static void schedule_ubi_work(struct ubi_device *ubi, struct ubi_work *wrk) static void schedule_ubi_work(struct ubi_device *ubi, struct ubi_work *wrk)
{ {
@ -740,7 +654,6 @@ static int wear_leveling_worker(struct ubi_device *ubi, struct ubi_work *wrk,
int cancel) int cancel)
{ {
int err, scrubbing = 0, torture = 0; int err, scrubbing = 0, torture = 0;
struct ubi_wl_prot_entry *uninitialized_var(pe);
struct ubi_wl_entry *e1, *e2; struct ubi_wl_entry *e1, *e2;
struct ubi_vid_hdr *vid_hdr; struct ubi_vid_hdr *vid_hdr;
@ -857,23 +770,17 @@ static int wear_leveling_worker(struct ubi_device *ubi, struct ubi_work *wrk,
* The LEB has not been moved because the volume is being * The LEB has not been moved because the volume is being
* deleted or the PEB has been put meanwhile. We should prevent * deleted or the PEB has been put meanwhile. We should prevent
* this PEB from being selected for wear-leveling movement * this PEB from being selected for wear-leveling movement
* again, so put it to the protection tree. * again, so put it to the protection queue.
*/ */
dbg_wl("canceled moving PEB %d", e1->pnum); dbg_wl("canceled moving PEB %d", e1->pnum);
ubi_assert(err == 1); ubi_assert(err == 1);
pe = kmalloc(sizeof(struct ubi_wl_prot_entry), GFP_NOFS);
if (!pe) {
err = -ENOMEM;
goto out_error;
}
ubi_free_vid_hdr(ubi, vid_hdr); ubi_free_vid_hdr(ubi, vid_hdr);
vid_hdr = NULL; vid_hdr = NULL;
spin_lock(&ubi->wl_lock); spin_lock(&ubi->wl_lock);
prot_tree_add(ubi, e1, pe, U_PROTECTION); prot_queue_add(ubi, e1);
ubi_assert(!ubi->move_to_put); ubi_assert(!ubi->move_to_put);
ubi->move_from = ubi->move_to = NULL; ubi->move_from = ubi->move_to = NULL;
ubi->wl_scheduled = 0; ubi->wl_scheduled = 0;
@ -1075,7 +982,6 @@ static int erase_worker(struct ubi_device *ubi, struct ubi_work *wl_wrk,
kfree(wl_wrk); kfree(wl_wrk);
spin_lock(&ubi->wl_lock); spin_lock(&ubi->wl_lock);
ubi->abs_ec += 1;
wl_tree_add(e, &ubi->free); wl_tree_add(e, &ubi->free);
spin_unlock(&ubi->wl_lock); spin_unlock(&ubi->wl_lock);
@ -1083,7 +989,7 @@ static int erase_worker(struct ubi_device *ubi, struct ubi_work *wl_wrk,
* One more erase operation has happened, take care about * One more erase operation has happened, take care about
* protected physical eraseblocks. * protected physical eraseblocks.
*/ */
check_protection_over(ubi); serve_prot_queue(ubi);
/* And take care about wear-leveling */ /* And take care about wear-leveling */
err = ensure_wear_leveling(ubi); err = ensure_wear_leveling(ubi);
@ -1220,7 +1126,7 @@ int ubi_wl_put_peb(struct ubi_device *ubi, int pnum, int torture)
paranoid_check_in_wl_tree(e, &ubi->scrub); paranoid_check_in_wl_tree(e, &ubi->scrub);
rb_erase(&e->u.rb, &ubi->scrub); rb_erase(&e->u.rb, &ubi->scrub);
} else { } else {
err = prot_tree_del(ubi, e->pnum); err = prot_queue_del(ubi, e->pnum);
if (err) { if (err) {
ubi_err("PEB %d not found", pnum); ubi_err("PEB %d not found", pnum);
ubi_ro_mode(ubi); ubi_ro_mode(ubi);
@ -1284,7 +1190,7 @@ int ubi_wl_scrub_peb(struct ubi_device *ubi, int pnum)
} else { } else {
int err; int err;
err = prot_tree_del(ubi, e->pnum); err = prot_queue_del(ubi, e->pnum);
if (err) { if (err) {
ubi_err("PEB %d not found", pnum); ubi_err("PEB %d not found", pnum);
ubi_ro_mode(ubi); ubi_ro_mode(ubi);
@ -1315,7 +1221,7 @@ int ubi_wl_flush(struct ubi_device *ubi)
int err; int err;
/* /*
* Erase while the pending works queue is not empty, but not more then * Erase while the pending works queue is not empty, but not more than
* the number of currently pending works. * the number of currently pending works.
*/ */
dbg_wl("flush (%d pending works)", ubi->works_count); dbg_wl("flush (%d pending works)", ubi->works_count);
@ -1461,15 +1367,13 @@ static void cancel_pending(struct ubi_device *ubi)
*/ */
int ubi_wl_init_scan(struct ubi_device *ubi, struct ubi_scan_info *si) int ubi_wl_init_scan(struct ubi_device *ubi, struct ubi_scan_info *si)
{ {
int err; int err, i;
struct rb_node *rb1, *rb2; struct rb_node *rb1, *rb2;
struct ubi_scan_volume *sv; struct ubi_scan_volume *sv;
struct ubi_scan_leb *seb, *tmp; struct ubi_scan_leb *seb, *tmp;
struct ubi_wl_entry *e; struct ubi_wl_entry *e;
ubi->used = ubi->free = ubi->scrub = RB_ROOT; ubi->used = ubi->free = ubi->scrub = RB_ROOT;
ubi->prot.pnum = ubi->prot.aec = RB_ROOT;
spin_lock_init(&ubi->wl_lock); spin_lock_init(&ubi->wl_lock);
mutex_init(&ubi->move_mutex); mutex_init(&ubi->move_mutex);
init_rwsem(&ubi->work_sem); init_rwsem(&ubi->work_sem);
@ -1483,6 +1387,10 @@ int ubi_wl_init_scan(struct ubi_device *ubi, struct ubi_scan_info *si)
if (!ubi->lookuptbl) if (!ubi->lookuptbl)
return err; return err;
for (i = 0; i < UBI_PROT_QUEUE_LEN; i++)
INIT_LIST_HEAD(&ubi->pq[i]);
ubi->pq_head = 0;
list_for_each_entry_safe(seb, tmp, &si->erase, u.list) { list_for_each_entry_safe(seb, tmp, &si->erase, u.list) {
cond_resched(); cond_resched();
@ -1577,33 +1485,18 @@ int ubi_wl_init_scan(struct ubi_device *ubi, struct ubi_scan_info *si)
} }
/** /**
* protection_trees_destroy - destroy the protection RB-trees. * protection_queue_destroy - destroy the protection queue.
* @ubi: UBI device description object * @ubi: UBI device description object
*/ */
static void protection_trees_destroy(struct ubi_device *ubi) static void protection_queue_destroy(struct ubi_device *ubi)
{ {
struct rb_node *rb; int i;
struct ubi_wl_prot_entry *pe; struct ubi_wl_entry *e, *tmp;
rb = ubi->prot.aec.rb_node; for (i = 0; i < UBI_PROT_QUEUE_LEN; ++i) {
while (rb) { list_for_each_entry_safe(e, tmp, &ubi->pq[i], u.list) {
if (rb->rb_left) list_del(&e->u.list);
rb = rb->rb_left; kmem_cache_free(ubi_wl_entry_slab, e);
else if (rb->rb_right)
rb = rb->rb_right;
else {
pe = rb_entry(rb, struct ubi_wl_prot_entry, rb_aec);
rb = rb_parent(rb);
if (rb) {
if (rb->rb_left == &pe->rb_aec)
rb->rb_left = NULL;
else
rb->rb_right = NULL;
}
kmem_cache_free(ubi_wl_entry_slab, pe->e);
kfree(pe);
} }
} }
} }
@ -1616,7 +1509,7 @@ void ubi_wl_close(struct ubi_device *ubi)
{ {
dbg_wl("close the WL sub-system"); dbg_wl("close the WL sub-system");
cancel_pending(ubi); cancel_pending(ubi);
protection_trees_destroy(ubi); protection_queue_destroy(ubi);
tree_destroy(&ubi->used); tree_destroy(&ubi->used);
tree_destroy(&ubi->free); tree_destroy(&ubi->free);
tree_destroy(&ubi->scrub); tree_destroy(&ubi->scrub);
@ -1686,4 +1579,27 @@ static int paranoid_check_in_wl_tree(struct ubi_wl_entry *e,
return 1; return 1;
} }
/**
* paranoid_check_in_pq - check if wear-leveling entry is in the protection
* queue.
* @ubi: UBI device description object
* @e: the wear-leveling entry to check
*
* This function returns zero if @e is in @ubi->pq and %1 if it is not.
*/
static int paranoid_check_in_pq(struct ubi_device *ubi, struct ubi_wl_entry *e)
{
struct ubi_wl_entry *p;
int i;
for (i = 0; i < UBI_PROT_QUEUE_LEN; ++i)
list_for_each_entry(p, &ubi->pq[i], u.list)
if (p == e)
return 0;
ubi_err("paranoid check failed for PEB %d, EC %d, Protect queue",
e->pnum, e->ec);
ubi_dbg_dump_stack();
return 1;
}
#endif /* CONFIG_MTD_UBI_DEBUG_PARANOID */ #endif /* CONFIG_MTD_UBI_DEBUG_PARANOID */