From 03e361b25ee8dfb1fd9b890072c23c4aae01c6c7 Mon Sep 17 00:00:00 2001 From: Geert Uytterhoeven 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 Signed-off-by: Lee Jones --- 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 @@ 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]); } 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); -- 2.34.1