From: Yi Kuo <yi@yikuo.dev>
To: smfrench@gmail.com, linkinjeon@kernel.org
Cc: metze@samba.org, tom@talpey.com, linux-cifs@vger.kernel.org,
samba-technical@lists.samba.org, linux-kernel@vger.kernel.org,
Yi Kuo <yi@yikuo.dev>
Subject: [PATCH] smb: smbdirect: fix MR registration for coalesced SG lists
Date: Wed, 29 Apr 2026 10:25:25 +0800 [thread overview]
Message-ID: <4bf423bb.AU4AAJbgzlAAAAAAAAAABAMtJJMAAYKKIjQAAAAAAC-ZZgBp8Ww0@mailjet.com> (raw)
ib_dma_map_sg() modifies the provided scatterlist and returns the
number of mapped entries, which can be fewer than the requested
mr->sgt.nents if the DMA controller coalesces contiguous memory
segments. Passing the original, uncoalesced count to ib_map_mr_sg()
causes memory registration failures if coalescing actually occurs.
Capture the actual mapped count returned by ib_dma_map_sg() and pass it
to ib_map_mr_sg() to ensure correct MR registration.
Also update the ib_dma_map_sg() error logging to drop the error
pointer formatting, since the return value is an integer count
rather than an error code.
Signed-off-by: Yi Kuo <yi@yikuo.dev>
---
fs/smb/smbdirect/mr.c | 18 +++++++++---------
1 file changed, 9 insertions(+), 9 deletions(-)
diff --git a/fs/smb/smbdirect/mr.c b/fs/smb/smbdirect/mr.c
index 5228e699cd5d..058dc24bf544 100644
--- a/fs/smb/smbdirect/mr.c
+++ b/fs/smb/smbdirect/mr.c
@@ -269,7 +269,7 @@ smbdirect_connection_register_mr_io(struct smbdirect_socket *sc,
{
const struct smbdirect_socket_parameters *sp = &sc->parameters;
struct smbdirect_mr_io *mr;
- int ret, num_pages;
+ int ret, num_pages, num_mapped;
struct ib_reg_wr *reg_wr;
num_pages = iov_iter_npages(iter, sp->max_frmr_depth + 1);
@@ -300,19 +300,19 @@ smbdirect_connection_register_mr_io(struct smbdirect_socket *sc,
num_pages, iov_iter_count(iter), sp->max_frmr_depth);
smbdirect_iter_to_sgt(iter, &mr->sgt, sp->max_frmr_depth);
- ret = ib_dma_map_sg(sc->ib.dev, mr->sgt.sgl, mr->sgt.nents, mr->dir);
- if (!ret) {
+ num_mapped = ib_dma_map_sg(sc->ib.dev, mr->sgt.sgl, mr->sgt.nents, mr->dir);
+ if (!num_mapped) {
smbdirect_log_rdma_mr(sc, SMBDIRECT_LOG_ERR,
- "ib_dma_map_sg num_pages=%u dir=%x ret=%d (%1pe)\n",
- num_pages, mr->dir, ret, SMBDIRECT_DEBUG_ERR_PTR(ret));
+ "ib_dma_map_sg num_pages=%u dir=%x num_mapped=%d\n",
+ num_pages, mr->dir, num_mapped);
goto dma_map_error;
}
- ret = ib_map_mr_sg(mr->mr, mr->sgt.sgl, mr->sgt.nents, NULL, PAGE_SIZE);
- if (ret != mr->sgt.nents) {
+ ret = ib_map_mr_sg(mr->mr, mr->sgt.sgl, num_mapped, NULL, PAGE_SIZE);
+ if (ret != num_mapped) {
smbdirect_log_rdma_mr(sc, SMBDIRECT_LOG_ERR,
- "ib_map_mr_sg failed ret = %d nents = %u\n",
- ret, mr->sgt.nents);
+ "ib_map_mr_sg failed ret = %d num_mapped = %u\n",
+ ret, num_mapped);
goto map_mr_error;
}
--
2.54.0
next reply other threads:[~2026-04-29 2:25 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-04-29 2:25 Yi Kuo [this message]
2026-04-30 8:15 ` [PATCH] smb: smbdirect: fix MR registration for coalesced SG lists kernel test robot
[not found] <53188517.AWMAAJZSdBsAAAAAAAAABAMtJJkAAYKKIjQAAAAAAC-ZZgBp8Ww0@mailjet.com>
2026-04-29 8:00 ` Stefan Metzmacher
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