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authorSylvain Chouleur <sylvain.chouleur@intel.com>2016-07-15 22:36:30 +0300
committerMatt Fleming <matt@codeblueprint.co.uk>2016-09-09 18:08:42 +0300
commit21b3ddd39feecd2f4d6c52bcd30f0a4fa14f125a (patch)
tree40773635e6415ce23293c67eda0327dddec90ae7 /fs/efivarfs
parent217b27d4671a0a3f34147f1b341683d36b7457db (diff)
downloadlinux-21b3ddd39feecd2f4d6c52bcd30f0a4fa14f125a.tar.xz
efi: Don't use spinlocks for efi vars
All efivars operations are protected by a spinlock which prevents interruptions and preemption. This is too restricted, we just need a lock preventing concurrency. The idea is to use a semaphore of count 1 and to have two ways of locking, depending on the context: - In interrupt context, we call down_trylock(), if it fails we return an error - In normal context, we call down_interruptible() We don't use a mutex here because the mutex_trylock() function must not be called from interrupt context, whereas the down_trylock() can. Signed-off-by: Sylvain Chouleur <sylvain.chouleur@intel.com> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Cc: Leif Lindholm <leif.lindholm@linaro.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Sylvain Chouleur <sylvain.chouleur@gmail.com> Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
Diffstat (limited to 'fs/efivarfs')
-rw-r--r--fs/efivarfs/inode.c5
-rw-r--r--fs/efivarfs/super.c9
2 files changed, 11 insertions, 3 deletions
diff --git a/fs/efivarfs/inode.c b/fs/efivarfs/inode.c
index 1d73fc6dba13..cbb50cadcffc 100644
--- a/fs/efivarfs/inode.c
+++ b/fs/efivarfs/inode.c
@@ -105,7 +105,10 @@ static int efivarfs_create(struct inode *dir, struct dentry *dentry,
inode->i_private = var;
- efivar_entry_add(var, &efivarfs_list);
+ err = efivar_entry_add(var, &efivarfs_list);
+ if (err)
+ goto out;
+
d_instantiate(dentry, inode);
dget(dentry);
out:
diff --git a/fs/efivarfs/super.c b/fs/efivarfs/super.c
index 688ccc16b702..01e3d6e53944 100644
--- a/fs/efivarfs/super.c
+++ b/fs/efivarfs/super.c
@@ -161,7 +161,9 @@ static int efivarfs_callback(efi_char16_t *name16, efi_guid_t vendor,
kfree(name);
efivar_entry_size(entry, &size);
- efivar_entry_add(entry, &efivarfs_list);
+ err = efivar_entry_add(entry, &efivarfs_list);
+ if (err)
+ goto fail_inode;
inode_lock(inode);
inode->i_private = entry;
@@ -182,7 +184,10 @@ fail:
static int efivarfs_destroy(struct efivar_entry *entry, void *data)
{
- efivar_entry_remove(entry);
+ int err = efivar_entry_remove(entry);
+
+ if (err)
+ return err;
kfree(entry);
return 0;
}