linux-kernel - Applied "regmap: Allocate buffers with GFP_ATOMIC when fast

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Message-Id: <E1ZbYtH-0002F4-IN@finisterre>
Date:	Mon, 14 Sep 2015 19:54:11 +0100
From:	Mark Brown <broonie@...nel.org>
To:	Abhijeet Dharmapurikar <adharmap@...eaurora.org>,
	Stephen Boyd <sboyd@...eaurora.org>,
	Mark Brown <broonie@...nel.org>
Cc:	linux-kernel@...r.kernel.org
Subject: Applied "regmap: Allocate buffers with GFP_ATOMIC when fast_io == true" to the regmap tree

The patch

   regmap: Allocate buffers with GFP_ATOMIC when fast_io == true

has been applied to the regmap tree at

   git://git.kernel.org/pub/scm/linux/kernel/git/broonie/regmap.git 

All being well this means that it will be integrated into the linux-next
tree (usually sometime in the next 24 hours) and sent to Linus during
the next merge window (or sooner if it is a bug fix), however if
problems are discovered then the patch may be dropped or reverted.  

You may get further e-mails resulting from automated or manual testing
and review of the tree, please engage with people reporting problems and
send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they
should be sent as incremental updates against current git, existing
patches will not be replaced.

Please add any relevant lists and maintainers to the CCs when replying
to this mail.

Thanks,
Mark

>From b4a21fc275e99fc63c77b30da92ee497f8a7bdb6 Mon Sep 17 00:00:00 2001
From: Stephen Boyd <sboyd@...eaurora.org>
Date: Fri, 11 Sep 2015 16:37:05 -0700
Subject: [PATCH] regmap: Allocate buffers with GFP_ATOMIC when fast_io == true

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@...eaurora.org>
Signed-off-by: Stephen Boyd <sboyd@...eaurora.org>
Signed-off-by: Mark Brown <broonie@...nel.org>
---
 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 cc55788..f3b1445 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 afaf562..0b51190 100644
--- a/drivers/base/regmap/regmap.c
+++ b/drivers/base/regmap/regmap.c
@@ -561,6 +561,16 @@ 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);
@@ -1786,7 +1796,7 @@ 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;
-- 
2.5.0

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