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mfd: Stop setting refcounting pointers in original mfd_cell arrays

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Commit 1e29af62f2 ("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>
This commit is contained in:
Geert Uytterhoeven 2013-10-29 10:03:04 +01:00 committed by Lee Jones
parent 24f76f37aa
commit 03e361b25e
2 changed files with 10 additions and 9 deletions
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17
drivers/mfd/mfd-core.c
View file

@ -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]);
}

2
include/linux/mfd/core.h
View file

@ -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);