NVMe: Add a few calling convention notes
For the benefit of reviewers, add comments to a few functions describing
their calling context
Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>
diff --git a/drivers/block/nvme.c b/drivers/block/nvme.c
index ddc21ba..12062c1 100644
--- a/drivers/block/nvme.c
+++ b/drivers/block/nvme.c
@@ -155,6 +155,9 @@
* the bottom two bits of the ctx pointer to store the handler ID.
* Passing in a pointer that's not 4-byte aligned will cause a BUG.
* We can change this if it becomes a problem.
+ *
+ * May be called with local interrupts disabled and the q_lock held,
+ * or with interrupts enabled and no locks held.
*/
static int alloc_cmdid(struct nvme_queue *nvmeq, void *ctx, int handler,
unsigned timeout)
@@ -202,6 +205,9 @@
#define CMD_CTX_INVALID (0x314 + CMD_CTX_BASE)
#define CMD_CTX_FLUSH (0x318 + CMD_CTX_BASE)
+/*
+ * Called with local interrupts disabled and the q_lock held. May not sleep.
+ */
static unsigned long free_cmdid(struct nvme_queue *nvmeq, int cmdid)
{
unsigned long data;
@@ -326,7 +332,7 @@
}
}
-/* length is in bytes */
+/* length is in bytes. gfp flags indicates whether we may sleep. */
static struct nvme_prps *nvme_setup_prps(struct nvme_dev *dev,
struct nvme_common_command *cmd,
struct scatterlist *sg, int *len,
@@ -483,6 +489,9 @@
return nvme_submit_flush(nvmeq, ns, cmdid);
}
+/*
+ * Called with local interrupts disabled and the q_lock held. May not sleep.
+ */
static int nvme_submit_bio_queue(struct nvme_queue *nvmeq, struct nvme_ns *ns,
struct bio *bio)
{