From 03e361b25ee8dfb1fd9b890072c23c4aae01c6c7 Mon Sep 17 00:00:00 2001
From: Geert Uytterhoeven <geert@linux-m68k.org>
Date: Tue, 29 Oct 2013 10:03:04 +0100
Subject: [PATCH] mfd: Stop setting refcounting pointers in original mfd_cell
arrays
Commit 1e29af62f2b285bd18685da93c3ce8c33ca2d1db ("mfd: Add refcounting
support to mfd_cells") had to drop the "const" keyword on the "cell"
parameter of mfd_add_devices(), as it added the refcounting pointers
to the objects of the passed mfd_cell array itself.
However, the mfd core code operates on copies of the mfd_cell objects,
so there's no need to modify the originally passed objects.
Hence, move the setting of the refcounting pointers from mfd_add_devices()
to mfd_platform_add_cell(), where the copy of the mfd_cell objects is made.
mfd_clone_cell() can just pass (a copy of) the original usage_count
pointer.
This allows to make the "cell" parameter of mfd_add_devices() "const"
again, and avoids future race conditions when registering multiple
instances of the same device in parallel.
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
---
drivers/mfd/mfd-core.c | 17 +++++++++--------
include/linux/mfd/core.h | 2 +-
2 files changed, 10 insertions(+), 9 deletions(-)
diff --git a/drivers/mfd/mfd-core.c b/drivers/mfd/mfd-core.c
index f421586f29fb..8736f4539bc0 100644
--- a/drivers/mfd/mfd-core.c
+++ b/drivers/mfd/mfd-core.c
@@ -63,7 +63,8 @@ int mfd_cell_disable(struct platform_device *pdev)
EXPORT_SYMBOL(mfd_cell_disable);
static int mfd_platform_add_cell(struct platform_device *pdev,
- const struct mfd_cell *cell)
+ const struct mfd_cell *cell,
+ atomic_t *usage_count)
{
if (!cell)
return 0;
@@ -72,11 +73,12 @@ static int mfd_platform_add_cell(struct platform_device *pdev,
if (!pdev->mfd_cell)
return -ENOMEM;
+ pdev->mfd_cell->usage_count = usage_count;
return 0;
}
static int mfd_add_device(struct device *parent, int id,
- const struct mfd_cell *cell,
+ const struct mfd_cell *cell, atomic_t *usage_count,
struct resource *mem_base,
int irq_base, struct irq_domain *domain)
{
@@ -115,7 +117,7 @@ static int mfd_add_device(struct device *parent, int id,
goto fail_res;
}
- ret = mfd_platform_add_cell(pdev, cell);
+ ret = mfd_platform_add_cell(pdev, cell, usage_count);
if (ret)
goto fail_res;
@@ -180,7 +182,7 @@ static int mfd_add_device(struct device *parent, int id,
}
int mfd_add_devices(struct device *parent, int id,
- struct mfd_cell *cells, int n_devs,
+ const struct mfd_cell *cells, int n_devs,
struct resource *mem_base,
int irq_base, struct irq_domain *domain)
{
@@ -195,8 +197,7 @@ int mfd_add_devices(struct device *parent, int id,
for (i = 0; i < n_devs; i++) {
atomic_set(&cnts[i], 0);
- cells[i].usage_count = &cnts[i];
- ret = mfd_add_device(parent, id, cells + i, mem_base,
+ ret = mfd_add_device(parent, id, cells + i, cnts + i, mem_base,
irq_base, domain);
if (ret)
break;
@@ -259,8 +260,8 @@ int mfd_clone_cell(const char *cell, const char **clones, size_t n_clones)
for (i = 0; i < n_clones; i++) {
cell_entry.name = clones[i];
/* don't give up if a single call fails; just report error */
- if (mfd_add_device(pdev->dev.parent, -1, &cell_entry, NULL, 0,
- NULL))
+ if (mfd_add_device(pdev->dev.parent, -1, &cell_entry,
+ cell_entry.usage_count, NULL, 0, NULL))
dev_err(dev, "failed to create platform device '%s'\n",
clones[i]);
}
diff --git a/include/linux/mfd/core.h b/include/linux/mfd/core.h
index cebe97ee98b8..60ced604664f 100644
--- a/include/linux/mfd/core.h
+++ b/include/linux/mfd/core.h
@@ -98,7 +98,7 @@ static inline const struct mfd_cell *mfd_get_cell(struct platform_device *pdev)
}
extern int mfd_add_devices(struct device *parent, int id,
- struct mfd_cell *cells, int n_devs,
+ const struct mfd_cell *cells, int n_devs,
struct resource *mem_base,
int irq_base, struct irq_domain *irq_domain);
--
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