linux-kernel - [PATCH 5.19 003/365] RDMA: Handle the return code from dma_resv_wait

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Date:   Tue, 23 Aug 2022 09:58:24 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, stable@...nel.org,
        Maor Gottlieb <maorg@...dia.com>,
        Jason Gunthorpe <jgg@...dia.com>,
        Leon Romanovsky <leon@...nel.org>
Subject: [PATCH 5.19 003/365] RDMA: Handle the return code from dma_resv_wait_timeout() properly

From: Jason Gunthorpe <jgg@...dia.com>

commit b16de8b9e7d1aae169d059c3a0dd9a881a3c0d1d upstream.

ib_umem_dmabuf_map_pages() returns 0 on success and -ERRNO on failure.

dma_resv_wait_timeout() uses a different scheme:

 * Returns -ERESTARTSYS if interrupted, 0 if the wait timed out, or
 * greater than zero on success.

This results in ib_umem_dmabuf_map_pages() being non-functional as a
positive return will be understood to be an error by drivers.

Fixes: f30bceab16d1 ("RDMA: use dma_resv_wait() instead of extracting the fence")
Cc: stable@...nel.org
Link: https://lore.kernel.org/r/0-v1-d8f4e1fa84c8+17-rdma_dmabuf_fix_jgg@nvidia.com
Tested-by: Maor Gottlieb <maorg@...dia.com>
Signed-off-by: Jason Gunthorpe <jgg@...dia.com>
Signed-off-by: Leon Romanovsky <leon@...nel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 drivers/infiniband/core/umem_dmabuf.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/infiniband/core/umem_dmabuf.c b/drivers/infiniband/core/umem_dmabuf.c
index fce80a4a5147..04c04e6d24c3 100644
--- a/drivers/infiniband/core/umem_dmabuf.c
+++ b/drivers/infiniband/core/umem_dmabuf.c
@@ -18,6 +18,7 @@ int ib_umem_dmabuf_map_pages(struct ib_umem_dmabuf *umem_dmabuf)
 	struct scatterlist *sg;
 	unsigned long start, end, cur = 0;
 	unsigned int nmap = 0;
+	long ret;
 	int i;
 
 	dma_resv_assert_held(umem_dmabuf->attach->dmabuf->resv);
@@ -67,9 +68,14 @@ int ib_umem_dmabuf_map_pages(struct ib_umem_dmabuf *umem_dmabuf)
 	 * may be not up-to-date. Wait for the exporter to finish
 	 * the migration.
 	 */
-	return dma_resv_wait_timeout(umem_dmabuf->attach->dmabuf->resv,
+	ret = dma_resv_wait_timeout(umem_dmabuf->attach->dmabuf->resv,
 				     DMA_RESV_USAGE_KERNEL,
 				     false, MAX_SCHEDULE_TIMEOUT);
+	if (ret < 0)
+		return ret;
+	if (ret == 0)
+		return -ETIMEDOUT;
+	return 0;
 }
 EXPORT_SYMBOL(ib_umem_dmabuf_map_pages);
 
-- 
2.37.2