Merge tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi

Pull SCSI fix from James Bottomley:
 "Fix to zone block devices to make the maximum segment count match what
  the block layer is capable of"

* tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
  scsi: sd_zbc: block: Respect bio vector limits for REPORT ZONES buffer

Author: torvalds

block/bio.c

@@ -611,7 +611,7 @@ 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);
 }

drivers/scsi/sd_zbc.c

@@ -169,6 +169,7 @@ 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;
 
@@ -180,12 +181,15 @@ 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);

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;