trigger: always use GFP_ATOMIC on allocation

in_atomic() function should not be used inside a driver, and it does not guarantee atomic context detection. Following the comment from the kernel source /* * Are we running in atomic context? WARNING: this macro cannot * always detect atomic context; in particular, it cannot know about * held spinlocks in non-preemptible kernels. Thus it should not be * used in the general case to determine whether sleeping is possible. * Do not use in_atomic() in driver code. */ Signed-off-by: Federico Vaga <federico.vaga@cern.ch>

trigger: always use GFP_ATOMIC on allocation
in_atomic() function should not be used inside a driver, and it does not guarantee atomic context detection. Following the comment from the kernel source /* * Are we running in atomic context? WARNING: this macro cannot * always detect atomic context; in particular, it cannot know about * held spinlocks in non-preemptible kernels. Thus it should not be * used in the general case to determine whether sleeping is possible. * Do not use in_atomic() in driver code. */ Signed-off-by: Federico Vaga <federico.vaga@cern.ch>
f5a34778 · Federico Vaga · d7861915 · f5a34778
Commit f5a34778 authored Apr 07, 2014 by Federico Vaga
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Showing with 8 additions and 7 deletions

fa-zio-trg.c kernel/fa-zio-trg.c +8 -7

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--- a/kernel/fa-zio-trg.c
+++ b/kernel/fa-zio-trg.c
@@ -291,10 +291,6 @@ static int zfat_arm_trigger(struct zio_ti *ti)
 	uint32_t dev_mem_off;
 	int i, err = 0;
 	struct zio_attribute *ti_zattr = ti->zattr_set.std_zattr;
-	gfp_t gfp;
-
-	/* if fsm-auto-start is active, we re-allocate at interrupt time */
-	gfp = in_atomic() ? GFP_ATOMIC : GFP_KERNEL;

 	dev_dbg(msgdev, "Arming trigger\n");

@@ -316,8 +312,12 @@ static int zfat_arm_trigger(struct zio_ti *ti)
 		return -EINVAL;
 	}

-	/* Allocate a new block for DMA transfer */
-	zfad_block = kmalloc(sizeof(struct zfad_block) * fa->n_shots, gfp);
+	/*
+	 * Allocate a new block for DMA transfer. Sometimes we are in an
+	 * atomic context and we cannot use in_atomic()
+	 */
+	zfad_block = kmalloc(sizeof(struct zfad_block) * fa->n_shots,
+			     GFP_ATOMIC);
 	if (!zfad_block)
 		return -ENOMEM;

@@ -347,7 +347,8 @@ static int zfat_arm_trigger(struct zio_ti *ti)
 	/* Allocate ZIO blocks */
 	for (i = 0; i < fa->n_shots; ++i) {
 		dev_dbg(msgdev, "Allocating block %d ...\n", i);
-		block = zio_buffer_alloc_block(interleave->bi, size, gfp);
+		block = zio_buffer_alloc_block(interleave->bi, size,
+					       GFP_ATOMIC);
 		if (!block) {
 			dev_err(msgdev,
 				"\narm trigger fail, cannot allocate block\n");