Commit Graph

39 Commits

Author SHA1 Message Date
Linus Torvalds d2c3ac7e7e Merge branch 'for-4.2' of git://linux-nfs.org/~bfields/linux
Pull nfsd updates from Bruce Fields:
 "A relatively quiet cycle, with a mix of cleanup and smaller bugfixes"

* 'for-4.2' of git://linux-nfs.org/~bfields/linux: (24 commits)
  sunrpc: use sg_init_one() in krb5_rc4_setup_enc/seq_key()
  nfsd: wrap too long lines in nfsd4_encode_read
  nfsd: fput rd_file from XDR encode context
  nfsd: take struct file setup fully into nfs4_preprocess_stateid_op
  nfsd: refactor nfs4_preprocess_stateid_op
  nfsd: clean up raparams handling
  nfsd: use swap() in sort_pacl_range()
  rpcrdma: Merge svcrdma and xprtrdma modules into one
  svcrdma: Add a separate "max data segs macro for svcrdma
  svcrdma: Replace GFP_KERNEL in a loop with GFP_NOFAIL
  svcrdma: Keep rpcrdma_msg fields in network byte-order
  svcrdma: Fix byte-swapping in svc_rdma_sendto.c
  nfsd: Update callback sequnce id only CB_SEQUENCE success
  nfsd: Reset cb_status in nfsd4_cb_prepare() at retrying
  svcrdma: Remove svc_rdma_xdr_decode_deferred_req()
  SUNRPC: Move EXPORT_SYMBOL for svc_process
  uapi/nfs: Add NFSv4.1 ACL definitions
  nfsd: Remove dead declarations
  nfsd: work around a gcc-5.1 warning
  nfsd: Checking for acl support does not require fetching any acls
  ...
2015-06-27 10:14:39 -07:00
Chuck Lever 30b7e246a6 svcrdma: Keep rpcrdma_msg fields in network byte-order
Fields in struct rpcrdma_msg are __be32. Don't byte-swap these
fields when decoding RPC calls and then swap them back for the
reply. For the most part, they can be left alone.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2015-06-04 16:55:59 -04:00
Michael Wang bc0f1d7153 IB/Verbs: Use management helper rdma_cap_read_multi_sge()
Introduce helper rdma_cap_read_multi_sge() to help us check if the port of an
IB device support RDMA Read Multiple Scatter-Gather Entries.

Signed-off-by: Michael Wang <yun.wang@profitbricks.com>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Tested-by: Ira Weiny <ira.weiny@intel.com>
Reviewed-by: Sean Hefty <sean.hefty@intel.com>
Reviewed-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Tested-by: Doug Ledford <dledford@redhat.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
2015-05-18 13:35:05 -04:00
Michael Wang 3de2c31ce7 IB/Verbs: Reform IB-ulp xprtrdma
Use raw management helpers to reform IB-ulp xprtrdma.

Signed-off-by: Michael Wang <yun.wang@profitbricks.com>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Tested-by: Ira Weiny <ira.weiny@intel.com>
Reviewed-by: Sean Hefty <sean.hefty@intel.com>
Reviewed-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Tested-by: Doug Ledford <dledford@redhat.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
2015-05-18 13:35:04 -04:00
Chuck Lever a97c331f9a svcrdma: Handle additional inline content
Most NFS RPCs place their large payload argument at the end of the
RPC header (eg, NFSv3 WRITE). For NFSv3 WRITE and SYMLINK, RPC/RDMA
sends the complete RPC header inline, and the payload argument in
the read list. Data in the read list is the last part of the XDR
stream.

One important case is not like this, however. NFSv4 COMPOUND is a
counted array of operations. A WRITE operation, with its large data
payload, can appear in the middle of the compound's operations
array. Thus NFSv4 WRITE compounds can have header content after the
WRITE payload.

The Linux client, for example, performs an NFSv4 WRITE like this:

  { PUTFH, WRITE, GETATTR }

Though RFC 5667 is not precise about this, the proper way to convey
this compound is to place the GETATTR inline, _after_ the front of
the RPC header. The receiver inserts the read list payload into the
XDR stream after the initial WRITE arguments, and before the GETATTR
operation, thanks to the value of the read list "position" field.

The Linux client currently sends the GETATTR at the end of the
RPC/RDMA read list, which is incorrect. It will be corrected in the
future.

The Linux server currently rejects NFSv4 compounds with inline
content after the read list. For the above NFSv4 WRITE compound, the
NFS compound header indicates there are three operations, but the
server finds nonsense when it looks in the XDR stream for the third
operation, and the compound fails with OP_ILLEGAL.

Move trailing inline content to the end of the XDR buffer's page
list. This presents incoming NFSv4 WRITE compounds to NFSD in the
same way the socket transport does.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2015-01-15 15:01:49 -05:00
Chuck Lever fcbeced5b4 svcrdma: Move read list XDR round-up logic
This is a pre-requisite for a subsequent patch.

Read list XDR round-up needs to be done _before_ additional inline
content is copied to the end of the XDR buffer's page list. Move
the logic added by commit e560e3b510 ("svcrdma: Add zero padding
if the client doesn't send it").

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2015-01-15 15:01:48 -05:00
Chuck Lever 0b056c224b svcrdma: Support RDMA_NOMSG requests
Currently the Linux server can not decode RDMA_NOMSG type requests.
Operations whose length exceeds the fixed size of RDMA SEND buffers,
like large NFSv4 CREATE(NF4LNK) operations, must be conveyed via
RDMA_NOMSG.

For an RDMA_MSG type request, the client sends the RPC/RDMA, RPC
headers, and some or all of the NFS arguments via RDMA SEND.

For an RDMA_NOMSG type request, the client sends just the RPC/RDMA
header via RDMA SEND. The request's read list contains elements for
the entire RPC message, including the RPC header.

NFSD expects the RPC/RMDA header and RPC header to be contiguous in
page zero of the XDR buffer. Add logic in the RDMA READ path to make
the read list contents land where the server prefers, when the
incoming message is a type RDMA_NOMSG message.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2015-01-15 15:01:47 -05:00
Chuck Lever 61edbcb7c7 svcrdma: rc_position sanity checking
An RPC/RDMA client may send large RPC arguments via a read
list. This is a list of scatter/gather elements which convey
RPC call arguments too large to fit in a small RDMA SEND.

Each entry in the read list has a "position" field, whose value is
the byte offset in the XDR stream where the data in that entry is to
be inserted. Entries which share the same "position" value make up
the same RPC argument. The receiver inserts entries with the same
position field value in list order into the XDR stream.

Currently the Linux NFS/RDMA server cannot handle receiving read
chunks in more than one position, mostly because no current client
sends read lists with elements in more than one position. As a
sanity check, ensure that all received chunks have the same
"rc_position."

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2015-01-15 15:01:47 -05:00
Chuck Lever e54524111f svcrdma: Plant reader function in struct svcxprt_rdma
The RDMA reader function doesn't change once an svcxprt_rdma is
instantiated. Instead of checking sc_devcap during every incoming
RPC, set the reader function once when the connection is accepted.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2015-01-15 15:01:46 -05:00
Chuck Lever 3fe04ee9f9 svcrdma: Scrub BUG_ON() and WARN_ON() call sites
Current convention is to avoid using BUG_ON() in places where an
oops could cause complete system failure.

Replace BUG_ON() call sites in svcrdma with an assertion error
message and allow execution to continue safely.

Some BUG_ON() calls are removed because they have never fired in
production (that we are aware of).

Some WARN_ON() calls are also replaced where a back trace is not
helpful; e.g., in a workqueue task.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2015-01-15 15:01:45 -05:00
Chuck Lever 2397aa8b51 svcrdma: Clean up read chunk counting
The byte_count argument is not used, and the function is called
only from one place.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2015-01-15 15:01:44 -05:00
Chuck Lever 597561bf6a svcrdma: Clean up dprintk
Nit: Fix inconsistent white space in dprintk messages.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2015-01-15 15:01:43 -05:00
Chuck Lever e560e3b510 svcrdma: Add zero padding if the client doesn't send it
See RFC 5666 section 3.7: clients don't have to send zero XDR
padding.

BugLink: https://bugzilla.linux-nfs.org/show_bug.cgi?id=246
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2014-07-22 16:40:21 -04:00
Steve Wise 83710fc753 svcrdma: Fence LOCAL_INV work requests
Fencing forces the invalidate to only happen after all prior send
work requests have been completed.

Signed-off-by: Steve Wise <swise@opengridcomputing.com>
Reported by : Devesh Sharma <Devesh.Sharma@Emulex.Com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2014-06-06 19:22:51 -04:00
Steve Wise 0bf4828983 svcrdma: refactor marshalling logic
This patch refactors the NFSRDMA server marshalling logic to
remove the intermediary map structures.  It also fixes an existing bug
where the NFSRDMA server was not minding the device fast register page
list length limitations.

Signed-off-by: Tom Tucker <tom@opengridcomputing.com>
Signed-off-by: Steve Wise <swise@opengridcomputing.com>
2014-06-06 19:22:50 -04:00
Tom Tucker 7e4359e261 Fix regression in NFSRDMA server
The server regression was caused by the addition of rq_next_page
(afc59400d6). There were a few places that
were missed with the update of the rq_respages array.

Signed-off-by: Tom Tucker <tom@ogc.us>
Tested-by: Steve Wise <swise@ogc.us>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2014-03-28 18:02:11 -04:00
J. Bruce Fields afc59400d6 nfsd4: cleanup: replace rq_resused count by rq_next_page pointer
It may be a matter of personal taste, but I find this makes the code
clearer.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2012-12-17 22:00:16 -05:00
Tom Tucker cec56c8ff5 svcrdma: Cleanup sparse warnings in the svcrdma module
The svcrdma transport was un-marshalling requests in-place. This resulted
in sparse warnings due to __beXX data containing both NBO and HBO data.

The code has been restructured to do byte-swapping as the header is
parsed instead of when the header is validated immediately after receipt.

Also moved extern declarations for the workqueue and memory pools to the
private header file.

Signed-off-by: Tom Tucker <tom@ogc.us>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2012-02-17 18:38:50 -05:00
Tom Tucker 4a84386fc2 svcrdma: Cleanup DMA unmapping in error paths.
There are several error paths in the code that do not unmap DMA. This
patch adds calls to svc_rdma_unmap_dma to free these DMA contexts.

Signed-off-by: Tom Tucker <tom@opengridcomputing.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2010-10-18 19:51:32 -04:00
Tom Tucker b432e6b3d9 svcrdma: Change DMA mapping logic to avoid the page_address kernel API
There was logic in the send path that assumed that a page containing data
to send to the client has a KVA. This is not always the case and can result
in data corruption when page_address returns zero and we end up DMA mapping
zero.

This patch changes the bus mapping logic to avoid page_address() where
necessary and converts all calls from ib_dma_map_single to ib_dma_map_page
in order to keep the map/unmap calls symmetric.

Signed-off-by: Tom Tucker <tom@ogc.us>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2010-10-18 19:51:31 -04:00
Neil Brown b48fa6b991 sunrpc: centralise most calls to svc_xprt_received
svc_xprt_received must be called when ->xpo_recvfrom has finished
receiving a message, so that the XPT_BUSY flag will be cleared and
if necessary, requeued for further work.

This call is currently made in each ->xpo_recvfrom function, often
from multiple different points.  In each case it is the earliest point
on a particular path where it is known that the protection provided by
XPT_BUSY is no longer needed.

However there are (still) some error paths which do not call
svc_xprt_received, and requiring each ->xpo_recvfrom to make the call
does not encourage robustness.

So: move the svc_xprt_received call to be made just after the
call to ->xpo_recvfrom(), and move it of the various ->xpo_recvfrom
methods.

This means that it may not be called at the earliest possible instant,
but this is unlikely to be a measurable performance issue.

Note that there are still other calls to svc_xprt_received as it is
also needed when an xprt is newly created.

Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
2010-05-03 08:33:00 -04:00
Joe Perches f64f9e7192 net: Move && and || to end of previous line
Not including net/atm/

Compiled tested x86 allyesconfig only
Added a > 80 column line or two, which I ignored.
Existing checkpatch plaints willfully, cheerfully ignored.

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2009-11-29 16:55:45 -08:00
Christian Engelmayer 59fb30660b sunrpc: potential memory leak in function rdma_read_xdr
In case the check on ch_count fails the cleanup path is skipped and the
previously allocated memory 'rpl_map', 'chl_map' is not freed.

Reported by Coverity.

Signed-off-by: Christian Engelmayer <christian.engelmayer@frequentis.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
2009-06-15 19:34:32 -07:00
Steve Wise d0687be7c7 svcrdma: Fix dma map direction for rdma read targets
The nfs server rdma transport was mapping rdma read target pages for
TO_DEVICE instead of FROM_DEVICE.  This causes data corruption on non
cache-coherent systems if frmrs are used.

Signed-off-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
2009-04-25 18:11:14 -04:00
Ilpo Järvinen b1721d2bb9 rpc/rdma: goto instead of copypaste
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-12-14 23:19:48 -08:00
Tom Tucker 146b6df6a5 svcrdma: Modify the RPC recv path to use FRMR when available
RPCRDMA requests that specify a read-list are fetched with RDMA_READ. Using
an FRMR to map the data sink improves NFSRDMA security on transports that
place the RDMA_READ data sink LKEY on the wire because the valid lifetime
of the MR is only the duration of the RDMA_READ. The LKEY is invalidated
when the last RDMA_READ WR completes.

Mapping the data sink also allows for very large amounts to data to be
fetched with a single WR, so if the client is also using FRMR, the entire
RPC read-list can be fetched with a single WR.

Signed-off-by: Tom Tucker <tom@opengridcomputing.com>
2008-10-06 14:46:01 -05:00
Tom Tucker 24b8b44780 svcrdma: Fix race between svc_rdma_recvfrom thread and the dto_tasklet
RDMA_READ completions are kept on a separate queue from the general
I/O request queue. Since a separate lock is used to protect the RDMA_READ
completion queue, a race exists between the dto_tasklet and the
svc_rdma_recvfrom thread where the dto_tasklet sets the XPT_DATA
bit and adds I/O to the read-completion queue. Concurrently, the
recvfrom thread checks the generic queue, finds it empty and resets
the XPT_DATA bit. A subsequent svc_xprt_enqueue will fail to enqueue
the transport for I/O and cause the transport to "stall".

The fix is to protect both lists with the same lock and set the XPT_DATA
bit with this lock held.

Signed-off-by: Tom Tucker <tom@opengridcomputing.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
2008-08-13 16:57:31 -04:00
Tom Tucker 87295b6c5c svcrdma: Add dma map count and WARN_ON
Add a dma map count in order to verify that all DMA mapping resources
have been freed when the transport is closed.

Signed-off-by: Tom Tucker <tom@opengridcomputing.com>
2008-07-02 15:01:56 -05:00
Tom Tucker f820c57ebf svcrdma: Use reply and chunk map for RDMA_READ processing
Modify the RDMA_READ processing to use the reply and chunk list mapping data
types. Also add a special purpose 'hdr_count' field in in the context to hold
the header page count instead of overloading the SGE length field and
corrupting the DMA map length.

Signed-off-by: Tom Tucker <tom@opengridcomputing.com>
2008-07-02 15:01:55 -05:00
Tom Tucker a6f911c04e svcrdma: Verify read-list fits within RPCSVC_MAXPAGES
A RDMA read-list cannot contain more elements than RPCSVC_MAXPAGES or
it will overflow the DTO context. Verify this when processing the
protocol header.

Signed-off-by: Tom Tucker <tom@opengridcomputing.com>
2008-05-19 07:34:02 -05:00
Tom Tucker 008fdbc571 svcrdma: Change svc_rdma_send_error return type to void
The svc_rdma_send_error function is called when an RPCRDMA protocol
error is detected. This function attempts to post an error reply message.
Since an error posting to a transport in error is ignored, change
the return type to void.

Signed-off-by: Tom Tucker <tom@opengridcomputing.com>
2008-05-19 07:34:01 -05:00
Tom Tucker 69500c43b4 svcrdma: Set rqstp transport address in rdma_read_complete function
The rdma_read_complete function needs to copy the rqstp transport address
from the transport. Failure to do so can result in using the wrong
authentication method for the RPC or bug checking if the rqstp address
is not valid.

Signed-off-by: Tom Tucker <tom@opengridcomputing.com>
2008-05-19 07:33:59 -05:00
Tom Tucker 02e7452de7 svcrdma: Simplify RDMA_READ deferral buffer management
An NFS_WRITE requires a set of RDMA_READ requests to fetch the write
data from the client. There are two principal pieces of data that
need to be tracked: the list of pages that comprise the completed RPC
and the SGE of dma mapped pages to refer to this list of pages. Previously
this whole bit was managed as a linked list of contexts with the
context containing the page list buried in this list. This patch
simplifies this processing by not keeping a linked list, but rather only
a pionter from the last submitted RDMA_READ's context to the context
that maps the set of pages that describe the RPC.  This significantly
simplifies this code path. SGE contexts are cleaned up inline in the DTO
path instead of at read completion time.

Signed-off-by: Tom Tucker <tom@opengridcomputing.com>
2008-05-19 07:33:51 -05:00
Tom Tucker 10a38c33f4 svcrdma: Remove unused READ_DONE context flags bit
The RDMACTXT_F_READ_DONE bit is not longer used. Remove it.

Signed-off-by: Tom Tucker <tom@opengridcomputing.com>
2008-05-19 07:33:50 -05:00
Tom Tucker d16d40093a svcrdma: Return error from rdma_read_xdr so caller knows to free context
The rdma_read_xdr function did not discriminate between no read-list and
an error posting the read-list. This results in a leak of a page if there
is an error posting the read-list.

Signed-off-by: Tom Tucker <tom@opengridcomputing.com>
2008-05-19 07:33:49 -05:00
Tom Tucker 0e7f011a19 svcrdma: Simplify receive buffer posting
The svcrdma transport provider currently allocates receive buffers
to the RQ through the xpo_release_rqst method. This approach is overly
complicated since it means that the rqstp rq_xprt_ctxt has to be
selectively set based on whether the RPC is going to be processed
immediately or deferred. Instead, just post the receive buffer when
we are certain that we are replying in the send_reply function.

Signed-off-by: Tom Tucker <tom@opengridcomputing.com>
2008-05-19 07:33:43 -05:00
Tom Tucker c8237a5fce SVCRDMA: Check num_sge when setting LAST_CTXT bit
The RDMACTXT_F_LAST_CTXT bit was getting set incorrectly
when the last chunk in the read-list spanned multiple pages. This
resulted in a kernel panic when the wrong context was used to
build the RPC iovec page list.

RDMA_READ is used to fetch RPC data from the client for
NFS_WRITE requests. A scatter-gather is used to map the
advertised client side buffer to the server-side iovec and
associated page list.

WR contexts are used to convey which scatter-gather entries are
handled by each WR. When the write data is large, a single RPC may
require multiple RDMA_READ requests so the contexts for a single RPC
are chained together in a linked list. The last context in this list
is marked with a bit RDMACTXT_F_LAST_CTXT so that when this WR completes,
the CQ handler code can enqueue the RPC for processing.

The code in rdma_read_xdr was setting this bit on the last two
contexts on this list when the last read-list chunk spanned multiple
pages. This caused the svc_rdma_recvfrom logic to incorrectly build
the RPC and caused the kernel to crash because the second-to-last
context doesn't contain the iovec page list.

Modified the condition that sets this bit so that it correctly detects
the last context for the RPC.

Signed-off-by: Tom Tucker <tom@opengridcomputing.com>
Tested-by: Roland Dreier <rolandd@cisco.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-03-26 11:24:19 -07:00
Roland Dreier d3073779f8 SVCRDMA: Use only 1 RDMA read scatter entry for iWARP adapters
The iWARP protocol limits RDMA read requests to a single scatter
entry.  NFS/RDMA has code in rdma_read_max_sge() that is supposed to
limit the sge_count for RDMA read requests to 1, but the code to do
that is inside an #ifdef RDMA_TRANSPORT_IWARP block.  In the mainline
kernel at least, RDMA_TRANSPORT_IWARP is an enum and not a
preprocessor #define, so the #ifdef'ed code is never compiled.

In my test of a kernel build with -j8 on an NFS/RDMA mount, this
problem eventually leads to trouble starting with:

    svcrdma: Error posting send = -22
    svcrdma : RDMA_READ error = -22

and things go downhill from there.

The trivial fix is to delete the #ifdef guard.  The check seems to be
a remnant of when the NFS/RDMA code was not merged and needed to
compile against multiple kernel versions, although I don't think it
ever worked as intended.  In any case now that the code is upstream
there's no need to test whether the RDMA_TRANSPORT_IWARP constant is
defined or not.

Without this patch, my kernel build on an NFS/RDMA mount using NetEffect
adapters quickly and 100% reproducibly failed with an error like:

    ld: final link failed: Software caused connection abort

With the patch applied I was able to complete a kernel build on the
same setup.

(Tom Tucker says this is "actually an _ancient_ remnant when it had to
compile against iWARP vs. non-iWARP enabled OFA trees.")

Signed-off-by: Roland Dreier <rolandd@cisco.com>
Acked-by: Tom Tucker <tom@opengridcomputing.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-03-24 11:25:25 -07:00
Tom Tucker d5b31be682 rdma: SVCRDMA recvfrom
This file implements the RDMA transport recvfrom function. The function
dequeues work reqeust completion contexts from an I/O list that it shares
with the I/O tasklet in svc_rdma_transport.c. For ONCRPC RDMA, an RPC may
not be complete when it is received. Instead, the RDMA header that precedes
the RPC message informs the transport where to get the RPC data from on
the client and where to place it in the RPC message before it is delivered
to the server. The svc_rdma_recvfrom function therefore, parses this RDMA
header and issues any necessary RDMA operations to fetch the remainder of
the RPC from the client.

Special handling is required when the request involves an RDMA_READ.
In this case, recvfrom submits the RDMA_READ requests to the underlying
transport driver and then returns 0. When the transport
completes the last RDMA_READ for the request, it enqueues it on a
read completion queue and enqueues the transport. The recvfrom code
favors this queue over the regular DTO queue when satisfying reads.

Signed-off-by: Tom Tucker <tom@opengridcomputing.com>
Acked-by: Neil Brown <neilb@suse.de>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
2008-02-01 16:42:14 -05:00