devcoredump: remove the useless gfp_t parameter in dev_coredumpv and dev_coredumpm

The dev_coredumpv() and dev_coredumpm() could not be used in atomic
context, because they call kvasprintf_const() and kstrdup() with
GFP_KERNEL parameter. The process is shown below:

dev_coredumpv(.., gfp_t gfp)
  dev_coredumpm(.., gfp_t gfp)
    dev_set_name
      kobject_set_name_vargs
        kvasprintf_const(GFP_KERNEL, ...); //may sleep
          kstrdup(s, GFP_KERNEL); //may sleep

This patch removes gfp_t parameter of dev_coredumpv() and dev_coredumpm()
and changes the gfp_t parameter of kzalloc() in dev_coredumpm() to
GFP_KERNEL in order to show they could not be used in atomic context.

Fixes: 833c95456a70 ("device coredump: add new device coredump class")
Reviewed-by: Brian Norris <briannorris@chromium.org>
Reviewed-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Duoming Zhou <duoming@zju.edu.cn>
Link: https://lore.kernel.org/r/df72af3b1862bac7d8e793d1f3931857d3779dfd.1654569290.git.duoming@zju.edu.cn
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 6 insertions, 10 deletions

diff --git a/drivers/base/devcoredump.c b/drivers/base/devcoredump.c
index f4d794d6bb85..8535f0bd5dfb 100644
--- a/drivers/base/devcoredump.c
+++ b/drivers/base/devcoredump.c
@@ -173,15 +173,13 @@ static void devcd_freev(void *data)
  * @dev: the struct device for the crashed device
  * @data: vmalloc data containing the device coredump
  * @datalen: length of the data
- * @gfp: allocation flags
  *
  * This function takes ownership of the vmalloc'ed data and will free
  * it when it is no longer used. See dev_coredumpm() for more information.
  */
-void dev_coredumpv(struct device *dev, void *data, size_t datalen,
-		   gfp_t gfp)
+void dev_coredumpv(struct device *dev, void *data, size_t datalen)
 {
-	dev_coredumpm(dev, NULL, data, datalen, gfp, devcd_readv, devcd_freev);
+	dev_coredumpm(dev, NULL, data, datalen, devcd_readv, devcd_freev);
 }
 EXPORT_SYMBOL_GPL(dev_coredumpv);
 
@@ -236,7 +234,6 @@ static ssize_t devcd_read_from_sgtable(char *buffer, loff_t offset,
  * @owner: the module that contains the read/free functions, use %THIS_MODULE
  * @data: data cookie for the @read/@free functions
  * @datalen: length of the data
- * @gfp: allocation flags
  * @read: function to read from the given buffer
  * @free: function to free the given buffer
  *
@@ -246,7 +243,7 @@ static ssize_t devcd_read_from_sgtable(char *buffer, loff_t offset,
  * function will be called to free the data.
  */
 void dev_coredumpm(struct device *dev, struct module *owner,
-		   void *data, size_t datalen, gfp_t gfp,
+		   void *data, size_t datalen,
 		   ssize_t (*read)(char *buffer, loff_t offset, size_t count,
 				   void *data, size_t datalen),
 		   void (*free)(void *data))
@@ -268,7 +265,7 @@ void dev_coredumpm(struct device *dev, struct module *owner,
 	if (!try_module_get(owner))
 		goto free;
 
-	devcd = kzalloc(sizeof(*devcd), gfp);
+	devcd = kzalloc(sizeof(*devcd), GFP_KERNEL);
 	if (!devcd)
 		goto put_module;
 
@@ -318,7 +315,6 @@ EXPORT_SYMBOL_GPL(dev_coredumpm);
  * @dev: the struct device for the crashed device
  * @table: the dump data
  * @datalen: length of the data
- * @gfp: allocation flags
  *
  * Creates a new device coredump for the given device. If a previous one hasn't
  * been read yet, the new coredump is discarded. The data lifetime is determined
@@ -326,9 +322,9 @@ EXPORT_SYMBOL_GPL(dev_coredumpm);
  * it will free the data.
  */
 void dev_coredumpsg(struct device *dev, struct scatterlist *table,
-		    size_t datalen, gfp_t gfp)
+		    size_t datalen)
 {
-	dev_coredumpm(dev, NULL, table, datalen, gfp, devcd_read_from_sgtable,
+	dev_coredumpm(dev, NULL, table, datalen, devcd_read_from_sgtable,
 		      devcd_free_sgtable);
 }
 EXPORT_SYMBOL_GPL(dev_coredumpsg);