[patch 2/6] scsi: warn and avoid creating dma caches if DMA supportis disabled

[David Rientjes]

__GFP_DMA may not be passed to scsi_{get,put}_host_cmd_pool() if
CONFIG_ZONE_DMA is disabled, which is now possible on x86.  If passed,
emit a warning and return.

Signed-off-by: David Rientjes <rientjes@xxxxxxxxxx>
---
 drivers/scsi/scsi.c |    9 +++++++++
 1 files changed, 9 insertions(+), 0 deletions(-)

diff --git a/drivers/scsi/scsi.c b/drivers/scsi/scsi.c
--- a/drivers/scsi/scsi.c
+++ b/drivers/scsi/scsi.c
@@ -359,6 +359,11 @@ EXPORT_SYMBOL(scsi_put_command);
 static struct scsi_host_cmd_pool *scsi_get_host_cmd_pool(gfp_t gfp_mask)
 {
 	struct scsi_host_cmd_pool *retval = NULL, *pool;
+
+#ifndef CONFIG_ZONE_DMA
+	if (WARN_ON_ONCE(gfp_mask & __GFP_DMA))
+		return NULL;
+#endif
 	/*
 	 * Select a command slab for this host and create it if not
 	 * yet existent.
@@ -393,6 +398,10 @@ static void scsi_put_host_cmd_pool(gfp_t gfp_mask)
 {
 	struct scsi_host_cmd_pool *pool;
 
+#ifndef CONFIG_ZONE_DMA
+        if (WARN_ON_ONCE(gfp_mask & __GFP_DMA))
+                return;
+#endif
 	mutex_lock(&host_cmd_pool_mutex);
 	pool = (gfp_mask & __GFP_DMA) ? &scsi_cmd_dma_pool :
 		&scsi_cmd_pool;
--
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