Commit 03e361b2 authored by Geert Uytterhoeven's avatar Geert Uytterhoeven Committed by Lee Jones
Browse files

mfd: Stop setting refcounting pointers in original mfd_cell arrays 



Commit 1e29af62 ("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: default avatarGeert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: default avatarLee Jones <lee.jones@linaro.org>
parent 24f76f37

drivers/mfd/mfd-core.c

+9 −8
Original line number Diff line number Diff line
@@ -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 @@ fail_alloc: 
}



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]);

	}

include/linux/mfd/core.h

+1 −1
Original line number Diff line number Diff line
@@ -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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