[PATCH] nvme: quieten sparse warning in valid LBA size check

[John Garry]

Currently building with C=1 generates the following warning:

  CC      drivers/nvme/host/core.o
  CHECK   drivers/nvme/host/core.c
drivers/nvme/host/core.c:2426:13: warning: unsigned value that used to be signed checked against zero?
drivers/nvme/host/core.c:2426:13: signed value source

This issue was introduced when using check_shl_overflow() to check for
invalid LBA size. Sparse is having trouble dealing with __bitwise __le64
conversion when passing to check_shl_overflow().

Resolve the issue by moving the check_shl_overflow() call to a separate
function, where types are not converted.

The id->lbaf[lbaf].ds < SECTOR_SHIFT check is dropped as
check_shl_overflow() is able to detect negative shifts.

Signed-off-by: John Garry <john.g.garry at oracle.com>

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index efaddab8296e0..d37fc70fe48aa 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -2379,6 +2379,11 @@ static int nvme_query_fdp_info(struct nvme_ns *ns, struct nvme_ns_info *info)
 	return ret;
 }
 
+static bool nvme_invalid_lba_sz(u64 nsze, signed int shift, sector_t *capacity)
+{
+	return check_shl_overflow(nsze, shift, capacity);
+}
+
 static int nvme_update_ns_info_block(struct nvme_ns *ns,
 		struct nvme_ns_info *info)
 {
@@ -2422,10 +2427,8 @@ static int nvme_update_ns_info_block(struct nvme_ns *ns,
 			goto out;
 	}
 
-	if (id->lbaf[lbaf].ds < SECTOR_SHIFT ||
-	    check_shl_overflow(le64_to_cpu(id->nsze),
-			       id->lbaf[lbaf].ds - SECTOR_SHIFT,
-			       &capacity)) {
+	if (nvme_invalid_lba_sz(le64_to_cpu(id->nsze),
+			id->lbaf[lbaf].ds - SECTOR_SHIFT, &capacity)) {
 		dev_warn_once(ns->ctrl->device,
 			"invalid LBA data size %u, skipping namespace\n",
 			id->lbaf[lbaf].ds);
-- 
2.43.5