From ea3f6572ecd9a7d357d2a7d8ede8b2efff59bcde Mon Sep 17 00:00:00 2001 From: Bartosz Golaszewski Date: Fri, 21 Sep 2018 06:40:14 -0700 Subject: [PATCH] UPSTREAM: nvmem: remove the global cell list Nvmem subsystem keeps a global list of cells that, for non-DT systems, can only be referenced by cell name, which makes it impossible to have more than one nvmem device with cells named the same. This patch makes every nvmem device the owner of the list of its cells. This effectively removes the support for non-DT systems, but it will be reintroduced following a different approach in subsequent patches. This isn't a problem as support for board files in nvmem is currently broken anyway: any user that would try to get an nvmem cell from the global cell list would remove the cell after the calling nvmem_cell_put(). This can cause anything from a subsequent user not being able to get the cell to double free errors if more users hold reference to the same cell at the same time. Fortunately there are no such users which allows us to rework this part. Bug: 154188491 Signed-off-by: Bartosz Golaszewski Signed-off-by: Srinivas Kandagatla Signed-off-by: Greg Kroah-Hartman (cherry picked from commit c7235ee3f4b86a01507a12e96a4875ba9b4be842) Signed-off-by: Will McVicker [willmcvicker: fix trivial merge conflicts] Change-Id: Ibedab956757f5eb94c3c6ff3a1476121624a9234 --- drivers/nvmem/core.c | 66 +++++++++++--------------------------------- 1 file changed, 16 insertions(+), 50 deletions(-) diff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c index 4ca1778c4bb8..8bc84ff21e88 100644 --- a/drivers/nvmem/core.c +++ b/drivers/nvmem/core.c @@ -39,6 +39,7 @@ struct nvmem_device { int flags; struct bin_attribute eeprom; struct device *base_dev; + struct list_head cells; nvmem_reg_read_t reg_read; nvmem_reg_write_t reg_write; void *priv; @@ -60,9 +61,6 @@ struct nvmem_cell { static DEFINE_MUTEX(nvmem_mutex); static DEFINE_IDA(nvmem_ida); -static LIST_HEAD(nvmem_cells); -static DEFINE_MUTEX(nvmem_cells_mutex); - #ifdef CONFIG_DEBUG_LOCK_ALLOC static struct lock_class_key eeprom_lock_key; #endif @@ -284,28 +282,11 @@ static struct nvmem_device *of_nvmem_find(struct device_node *nvmem_np) return to_nvmem_device(d); } -static struct nvmem_cell *nvmem_find_cell(const char *cell_id) -{ - struct nvmem_cell *p; - - mutex_lock(&nvmem_cells_mutex); - - list_for_each_entry(p, &nvmem_cells, node) - if (!strcmp(p->name, cell_id)) { - mutex_unlock(&nvmem_cells_mutex); - return p; - } - - mutex_unlock(&nvmem_cells_mutex); - - return NULL; -} - static void nvmem_cell_drop(struct nvmem_cell *cell) { - mutex_lock(&nvmem_cells_mutex); + mutex_lock(&nvmem_mutex); list_del(&cell->node); - mutex_unlock(&nvmem_cells_mutex); + mutex_unlock(&nvmem_mutex); of_node_put(cell->np); kfree(cell); } @@ -314,16 +295,15 @@ static void nvmem_device_remove_all_cells(const struct nvmem_device *nvmem) { struct nvmem_cell *cell, *p; - list_for_each_entry_safe(cell, p, &nvmem_cells, node) - if (cell->nvmem == nvmem) - nvmem_cell_drop(cell); + list_for_each_entry_safe(cell, p, &nvmem->cells, node) + nvmem_cell_drop(cell); } static void nvmem_cell_add(struct nvmem_cell *cell) { - mutex_lock(&nvmem_cells_mutex); - list_add_tail(&cell->node, &nvmem_cells); - mutex_unlock(&nvmem_cells_mutex); + mutex_lock(&nvmem_mutex); + list_add_tail(&cell->node, &cell->nvmem->cells); + mutex_unlock(&nvmem_mutex); } static int nvmem_cell_info_to_nvmem_cell(struct nvmem_device *nvmem, @@ -527,6 +507,7 @@ struct nvmem_device *nvmem_register(const struct nvmem_config *config) } kref_init(&nvmem->refcnt); + INIT_LIST_HEAD(&nvmem->cells); nvmem->id = rval; nvmem->owner = config->owner; @@ -697,29 +678,14 @@ static struct nvmem_device *__nvmem_device_get(struct device_node *np, { struct nvmem_device *nvmem = NULL; + if (!np) + return ERR_PTR(-ENOENT); + mutex_lock(&nvmem_mutex); - - if (np) { - nvmem = of_nvmem_find(np); - if (!nvmem) { - mutex_unlock(&nvmem_mutex); - return ERR_PTR(-EPROBE_DEFER); - } - } else { - struct nvmem_cell *cell = nvmem_find_cell(cell_id); - - if (cell) { - nvmem = cell->nvmem; - *cellp = cell; - } - - if (!nvmem) { - mutex_unlock(&nvmem_mutex); - return ERR_PTR(-ENOENT); - } - } - + nvmem = of_nvmem_find(np); mutex_unlock(&nvmem_mutex); + if (!nvmem) + return ERR_PTR(-EPROBE_DEFER); if (!try_module_get(nvmem->owner)) { dev_err(&nvmem->dev, @@ -897,7 +863,7 @@ nvmem_find_cell_by_node(struct nvmem_device *nvmem, struct device_node *np) struct nvmem_cell *cell = NULL; mutex_lock(&nvmem_mutex); - list_for_each_entry(cell, &nvmem_cells, node) { + list_for_each_entry(cell, &nvmem->cells, node) { if (np == cell->np) break; }