scsi: sd_zbc: block: Respect bio vector limits for REPORT ZONES buffer

commit e8007fad5457ea547ca63bb011fdb03213571c7e upstream.

The REPORT ZONES buffer size is currently limited by the HBA's maximum
segment count to ensure the buffer can be mapped. However, the block
layer further limits the number of iovec entries to 1024 when allocating
a bio.

To avoid allocation of buffers too large to be mapped, further restrict
the maximum buffer size to BIO_MAX_INLINE_VECS.

Replace the UIO_MAXIOV symbolic name with the more contextually
appropriate BIO_MAX_INLINE_VECS.

Fixes: b091ac616846 ("sd_zbc: Fix report zones buffer allocation")
Cc: stable@vger.kernel.org
Signed-off-by: Steve Siwinski <ssiwinski@atto.com>
Link: https://lore.kernel.org/r/20250508200122.243129-1-ssiwinski@atto.com
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/block/bio.c b/block/bio.c
index 4a8e7616995718ba5681d3a7d9ef3b87100168ac..b197abbaebc4644c5a920d9f4f361981cccb79a6 100644 (file)
--- a/block/bio.c
+++ b/block/bio.c
@@ -600,7 +600,7 @@ struct bio *bio_kmalloc(unsigned short nr_vecs, gfp_t gfp_mask)
 {
        struct bio *bio;
 
-       if (nr_vecs > UIO_MAXIOV)
+       if (nr_vecs > BIO_MAX_INLINE_VECS)
                return NULL;
        return kmalloc(struct_size(bio, bi_inline_vecs, nr_vecs), gfp_mask);
 }

diff --git a/drivers/scsi/sd_zbc.c b/drivers/scsi/sd_zbc.c
index 203df5e53b1a84d24f098ffddc132e8e35bd3f3d..9bbabae253e53b18deeb827ca027d590778d6037 100644 (file)
--- a/drivers/scsi/sd_zbc.c
+++ b/drivers/scsi/sd_zbc.c
@@ -202,6 +202,7 @@ static void *sd_zbc_alloc_report_buffer(struct scsi_disk *sdkp,
                                        unsigned int nr_zones, size_t *buflen)
 {
        struct request_queue *q = sdkp->disk->queue;
+       unsigned int max_segments;
        size_t bufsize;
        void *buf;
 
@@ -213,12 +214,15 @@ static void *sd_zbc_alloc_report_buffer(struct scsi_disk *sdkp,
         * Furthermore, since the report zone command cannot be split, make
         * sure that the allocated buffer can always be mapped by limiting the
         * number of pages allocated to the HBA max segments limit.
+        * Since max segments can be larger than the max inline bio vectors,
+        * further limit the allocated buffer to BIO_MAX_INLINE_VECS.
         */
        nr_zones = min(nr_zones, sdkp->zone_info.nr_zones);
        bufsize = roundup((nr_zones + 1) * 64, SECTOR_SIZE);
        bufsize = min_t(size_t, bufsize,
                        queue_max_hw_sectors(q) << SECTOR_SHIFT);
-       bufsize = min_t(size_t, bufsize, queue_max_segments(q) << PAGE_SHIFT);
+       max_segments = min(BIO_MAX_INLINE_VECS, queue_max_segments(q));
+       bufsize = min_t(size_t, bufsize, max_segments << PAGE_SHIFT);
 
        while (bufsize >= SECTOR_SIZE) {
                buf = kvzalloc(bufsize, GFP_KERNEL | __GFP_NORETRY);

diff --git a/include/linux/bio.h b/include/linux/bio.h
index 0286bada25ce724b8bcb54a7faf097b7224b03ee..b893418c3cc022355caf2581c767ec51d1c9de83 100644 (file)
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -11,6 +11,7 @@
 #include <linux/uio.h>
 
 #define BIO_MAX_VECS           256U
+#define BIO_MAX_INLINE_VECS    UIO_MAXIOV
 
 struct queue_limits;