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Subject[PATCH v2] regmap: Allocate buffers with GFP_ATOMIC when fast_io == true
Date
If a regmap is using fast_io, allocate the scratch buffer in
regmap_bulk_write() with GFP_ATOMIC instead of GFP_KERNEL.
Otherwise we may schedule while atomic.

Reported-by: Abhijeet Dharmapurikar <adharmap@codeaurora.org>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
---

Changes since v1:
* Only modify allocations in regmap_bulk_write() path

drivers/base/regmap/internal.h | 1 +
drivers/base/regmap/regmap.c | 12 +++++++++++-
2 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/drivers/base/regmap/internal.h b/drivers/base/regmap/internal.h
index 873ddf91c9d3..3470ec146f12 100644
--- a/drivers/base/regmap/internal.h
+++ b/drivers/base/regmap/internal.h
@@ -59,6 +59,7 @@ struct regmap {
regmap_lock lock;
regmap_unlock unlock;
void *lock_arg; /* This is passed to lock/unlock functions */
+ gfp_t alloc_flags;

struct device *dev; /* Device we do I/O on */
void *work_buf; /* Scratch buffer used to format I/O */
diff --git a/drivers/base/regmap/regmap.c b/drivers/base/regmap/regmap.c
index 29128c6af445..dc90f2ac332a 100644
--- a/drivers/base/regmap/regmap.c
+++ b/drivers/base/regmap/regmap.c
@@ -563,6 +563,16 @@ struct regmap *regmap_init(struct device *dev,
}
map->lock_arg = map;
}
+
+ /*
+ * When we write in fast-paths with regmap_bulk_write() don't allocate
+ * scratch buffers with sleeping allocations.
+ */
+ if ((bus && bus->fast_io) || config->fast_io)
+ map->alloc_flags = GFP_ATOMIC;
+ else
+ map->alloc_flags = GFP_KERNEL;
+
map->format.reg_bytes = DIV_ROUND_UP(config->reg_bits, 8);
map->format.pad_bytes = config->pad_bits / 8;
map->format.val_bytes = DIV_ROUND_UP(config->val_bits, 8);
@@ -1729,7 +1739,7 @@ out:
if (!val_count)
return -EINVAL;

- wval = kmemdup(val, val_count * val_bytes, GFP_KERNEL);
+ wval = kmemdup(val, val_count * val_bytes, map->alloc_flags);
if (!wval) {
dev_err(map->dev, "Error in memory allocation\n");
return -ENOMEM;
--
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project


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