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introduce memory_read_from_buffer() 

This patch introduces memory_read_from_buffer().

The only difference between memory_read_from_buffer() and
simple_read_from_buffer() is which address space the function copies to.

simple_read_from_buffer copies to user space memory.
memory_read_from_buffer copies to normal memory.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Doug Warzecha <Douglas_Warzecha@dell.com>
Cc: Zhang Rui <rui.zhang@intel.com>
Cc: Matt Domsch <Matt_Domsch@dell.com>
Cc: Abhay Salunke <Abhay_Salunke@dell.com>
Cc: Greg Kroah-Hartman <gregkh@suse.de>
Cc: Markus Rechberger <markus.rechberger@amd.com>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Cc: Bob Moore <robert.moore@intel.com>
Cc: Thomas Renninger <trenn@suse.de>
Cc: Len Brown <lenb@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: "Antonino A. Daplas" <adaplas@pol.net>
Cc: Krzysztof Helt <krzysztof.h1@poczta.fm>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
Cc: Michael Holzheu <holzheu@de.ibm.com>
Cc: Brian King <brking@us.ibm.com>
Cc: James E.J. Bottomley <James.Bottomley@HansenPartnership.com>
Cc: Andrew Vasquez <linux-driver@qlogic.com>
Cc: Seokmann Ju <seokmann.ju@qlogic.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Akinobu Mita 2008-06-05 22:46:21 -07:00 committed by Linus Torvalds
parent 3527fb326f
commit 93b071139a
2 changed files with 22 additions and 1 deletions
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18
fs/libfs.c
View File

@ -528,6 +528,23 @@ ssize_t simple_read_from_buffer(void __user *to, size_t count, loff_t *ppos,
return count;
}
ssize_t memory_read_from_buffer(void *to, size_t count, loff_t *ppos,
const void *from, size_t available)
{
loff_t pos = *ppos;
if (pos < 0)
return -EINVAL;
if (pos >= available)
return 0;
if (count > available - pos)
count = available - pos;
memcpy(to, from + pos, count);
*ppos = pos + count;
return count;
}
/*
* Transaction based IO.
* The file expects a single write which triggers the transaction, and then
@ -800,6 +817,7 @@ EXPORT_SYMBOL(simple_statfs);
EXPORT_SYMBOL(simple_sync_file);
EXPORT_SYMBOL(simple_unlink);
EXPORT_SYMBOL(simple_read_from_buffer);
EXPORT_SYMBOL(memory_read_from_buffer);
EXPORT_SYMBOL(simple_transaction_get);
EXPORT_SYMBOL(simple_transaction_read);
EXPORT_SYMBOL(simple_transaction_release);

5
include/linux/fs.h
View File

@ -2000,7 +2000,10 @@ extern int simple_fill_super(struct super_block *, int, struct tree_descr *);
extern int simple_pin_fs(struct file_system_type *, struct vfsmount **mount, int *count);
extern void simple_release_fs(struct vfsmount **mount, int *count);
extern ssize_t simple_read_from_buffer(void __user *, size_t, loff_t *, const void *, size_t);
extern ssize_t simple_read_from_buffer(void __user *to, size_t count,
loff_t *ppos, const void *from, size_t available);
extern ssize_t memory_read_from_buffer(void *to, size_t count, loff_t *ppos,
const void *from, size_t available);
#ifdef CONFIG_MIGRATION
extern int buffer_migrate_page(struct address_space *,