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svcrdma: Fix page leak in svc_rdma_recv_read_chunk()

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[ Upstream commit e814eecbe3bbeaa8b004d25a4b8974d232b765a9 ]

Commit 07d0ff3b0c ("svcrdma: Clean up Read chunk path") moved the
page saver logic so that it gets executed event when an error occurs.
In that case, the I/O is never posted, and those pages are then
leaked. Errors in this path, however, are quite rare.

Fixes: 07d0ff3b0c ("svcrdma: Clean up Read chunk path")
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Chuck Lever 2020-06-11 12:44:56 -04:00 committed by Greg Kroah-Hartman
parent fa6bd08869
commit 789be9705e
1 changed files with 21 additions and 7 deletions
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28
net/sunrpc/xprtrdma/svc_rdma_rw.c
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@ -677,7 +677,6 @@ static int svc_rdma_build_read_chunk(struct svc_rqst *rqstp,
struct svc_rdma_read_info *info,
__be32 *p)
{
unsigned int i;
int ret;
ret = -EINVAL;
@ -700,12 +699,6 @@ static int svc_rdma_build_read_chunk(struct svc_rqst *rqstp,
info->ri_chunklen += rs_length;
}
/* Pages under I/O have been copied to head->rc_pages.
* Prevent their premature release by svc_xprt_release() .
*/
for (i = 0; i < info->ri_readctxt->rc_page_count; i++)
rqstp->rq_pages[i] = NULL;
return ret;
}
@ -800,6 +793,26 @@ static int svc_rdma_build_pz_read_chunk(struct svc_rqst *rqstp,
return ret;
}
/* Pages under I/O have been copied to head->rc_pages. Ensure they
* are not released by svc_xprt_release() until the I/O is complete.
*
* This has to be done after all Read WRs are constructed to properly
* handle a page that is part of I/O on behalf of two different RDMA
* segments.
*
* Do this only if I/O has been posted. Otherwise, we do indeed want
* svc_xprt_release() to clean things up properly.
*/
static void svc_rdma_save_io_pages(struct svc_rqst *rqstp,
const unsigned int start,
const unsigned int num_pages)
{
unsigned int i;
for (i = start; i < num_pages + start; i++)
rqstp->rq_pages[i] = NULL;
}
/**
* svc_rdma_recv_read_chunk - Pull a Read chunk from the client
* @rdma: controlling RDMA transport
@ -853,6 +866,7 @@ int svc_rdma_recv_read_chunk(struct svcxprt_rdma *rdma, struct svc_rqst *rqstp,
ret = svc_rdma_post_chunk_ctxt(&info->ri_cc);
if (ret < 0)
goto out_err;
svc_rdma_save_io_pages(rqstp, 0, head->rc_page_count);
return 0;
out_err: