bdev/nvme: set max_num_segments based on controller limit

Fixes issue spdk#3269. Signed-off-by: Jim Harris <[email protected]> Change-Id: I48f8ef47841123c451421c53ad68714eff26722c Reviewed-on: https://review.spdk.io/gerrit/c/spdk/spdk/+/21952 Tested-by: SPDK CI Jenkins <[email protected]> Reviewed-by: Konrad Sztyber <[email protected]> Reviewed-by: Shuhei Matsumoto <[email protected]> Community-CI: Mellanox Build Bot
Mellanox · Feb 26, 2024 · e3367a2 · e3367a2
1 parent 6f3e277
commit e3367a2
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diff --git a/module/bdev/nvme/bdev_nvme.c b/module/bdev/nvme/bdev_nvme.c
@@ -4046,6 +4046,21 @@ nvme_disk_create(struct spdk_bdev *disk, const char *base_name,
 	if (opts && opts->io_queue_requests) {
 		disk->max_num_segments = opts->io_queue_requests / 2;
 	}
+	if (spdk_nvme_ctrlr_get_flags(ctrlr) & SPDK_NVME_CTRLR_SGL_SUPPORTED) {
+		/* The nvme driver will try to split I/O that have too many
+		 * SGEs, but it doesn't work if that last SGE doesn't end on
+		 * an aggregate total that is block aligned. The bdev layer has
+		 * a more robust splitting framework, so use that instead for
+		 * this case. (See issue #3269.)
+		 */
+		uint16_t max_sges = spdk_nvme_ctrlr_get_max_sges(ctrlr);
+
+		if (disk->max_num_segments == 0) {
+			disk->max_num_segments = max_sges;
+		} else {
+			disk->max_num_segments = spdk_min(disk->max_num_segments, max_sges);
+		}
+	}
 	disk->optimal_io_boundary = spdk_nvme_ns_get_optimal_io_boundary(ns);
 
 	nguid = spdk_nvme_ns_get_nguid(ns);

diff --git a/test/unit/lib/bdev/nvme/bdev_nvme.c/bdev_nvme_ut.c b/test/unit/lib/bdev/nvme/bdev_nvme.c/bdev_nvme_ut.c
@@ -39,6 +39,7 @@ DEFINE_STUB_V(spdk_nvme_ctrlr_set_remove_cb, (struct spdk_nvme_ctrlr *ctrlr,
 		spdk_nvme_remove_cb remove_cb, void *remove_ctx));
 
 DEFINE_STUB(spdk_nvme_ctrlr_get_flags, uint64_t, (struct spdk_nvme_ctrlr *ctrlr), 0);
+DEFINE_STUB(spdk_nvme_ctrlr_get_max_sges, uint16_t, (const struct spdk_nvme_ctrlr *ctrlr), 0);
 
 DEFINE_STUB(accel_channel_create, int, (void *io_device, void *ctx_buf), 0);
 DEFINE_STUB_V(accel_channel_destroy, (void *io_device, void *ctx_buf));