Add "no BKL needed" comments to several drivers

This documents the fact that somebody looked at the relevant open()
functions and concluded that, due to their trivial nature, no locking was
needed.

Signed-off-by: Jonathan Corbet <corbet@lwn.net>

diff --git a/arch/cris/arch-v10/drivers/eeprom.c b/arch/cris/arch-v10/drivers/eeprom.c
index f1cac9dc75b8150bfdad17e904450f7738428438..40c6fe4c06f4a010a7fd4a264d36f2d4ac3cf5c9 100644 (file)
--- a/arch/cris/arch-v10/drivers/eeprom.c
+++ b/arch/cris/arch-v10/drivers/eeprom.c
@@ -375,7 +375,7 @@ int __init eeprom_init(void)
 }
 
 /* Opens the device. */
-
+/* BKL not needed: no global resources accessed */
 static int eeprom_open(struct inode * inode, struct file * file)
 {
 

diff --git a/arch/cris/arch-v32/drivers/cryptocop.c b/arch/cris/arch-v32/drivers/cryptocop.c
index 9fb58202be99b8d54d729c161dba9983cc29352d..c17204289575865513974b9e41fdea1730981a70 100644 (file)
--- a/arch/cris/arch-v32/drivers/cryptocop.c
+++ b/arch/cris/arch-v32/drivers/cryptocop.c
@@ -2302,7 +2302,7 @@ static int cryptocop_job_setup(struct cryptocop_prio_job **pj, struct cryptocop_
        return 0;
 }
 
-
+/* No BKL needed here - no global resources accessed */
 static int cryptocop_open(struct inode *inode, struct file *filp)
 {
        int p = iminor(inode);

diff --git a/drivers/char/cs5535_gpio.c b/drivers/char/cs5535_gpio.c
index c0a4a0bb509e77397875b023bc4ad4f1324946bf..628e3d3249d216fed6842af53c514514989ff84f 100644 (file)
--- a/drivers/char/cs5535_gpio.c
+++ b/drivers/char/cs5535_gpio.c
@@ -153,6 +153,8 @@ static ssize_t cs5535_gpio_read(struct file *file, char __user *buf,
        return count;
 }
 
+/* No BKL needed here - "mask" is the only global resource used
+   here and it's a boot-time parameter */
 static int cs5535_gpio_open(struct inode *inode, struct file *file)
 {
        u32 m = iminor(inode);

diff --git a/drivers/char/dtlk.c b/drivers/char/dtlk.c
index abde6ddefe696e7e0af352e918085c68a83f4d89..433388c6023565fdb0f7dffe6587e86b172ecc17 100644 (file)
--- a/drivers/char/dtlk.c
+++ b/drivers/char/dtlk.c
@@ -288,6 +288,8 @@ static int dtlk_ioctl(struct inode *inode,
        }
 }
 
+/* No BKL needed here; "dtlk_busy" is the only global resource,
+   and it is not ever set by anybody (test is broken) */
 static int dtlk_open(struct inode *inode, struct file *file)
 {
        TRACE_TEXT("(dtlk_open");

diff --git a/drivers/char/pc8736x_gpio.c b/drivers/char/pc8736x_gpio.c
index ecfaf180e5bd8b106ee12e06da33fc0c1a88f702..8715dc9f4a531f2f64445642970e6c603f04ba82 100644 (file)
--- a/drivers/char/pc8736x_gpio.c
+++ b/drivers/char/pc8736x_gpio.c
@@ -212,6 +212,7 @@ static struct nsc_gpio_ops pc8736x_gpio_ops = {
        .gpio_current   = pc8736x_gpio_current
 };
 
+/* No BKL needed here; no global resources accessed */
 static int pc8736x_gpio_open(struct inode *inode, struct file *file)
 {
        unsigned m = iminor(inode);

diff --git a/drivers/char/ppdev.c b/drivers/char/ppdev.c
index 3aab837d9480ae57e66fb9f438e76efd263fea95..ce1987574888370c86b5076e51905dfe5b6bfa6f 100644 (file)
--- a/drivers/char/ppdev.c
+++ b/drivers/char/ppdev.c
@@ -633,6 +633,7 @@ static int pp_ioctl(struct inode *inode, struct file *file,
        return 0;
 }
 
+/* No BKL needed here: only local resources used */
 static int pp_open (struct inode * inode, struct file * file)
 {
        unsigned int minor = iminor(inode);

diff --git a/drivers/char/scx200_gpio.c b/drivers/char/scx200_gpio.c
index 99e5272e3c53e1ef1aa32f0733b1bbf0e9f2487e..be2c623a9862f6cfa80cfe0170acc3ce15e3161c 100644 (file)
--- a/drivers/char/scx200_gpio.c
+++ b/drivers/char/scx200_gpio.c
@@ -46,6 +46,7 @@ struct nsc_gpio_ops scx200_gpio_ops = {
 };
 EXPORT_SYMBOL_GPL(scx200_gpio_ops);
 
+/* No BKL needed here: no global resources used */
 static int scx200_gpio_open(struct inode *inode, struct file *file)
 {
        unsigned m = iminor(inode);

diff --git a/drivers/char/tb0219.c b/drivers/char/tb0219.c
index 4c431cb7cf1b1f21f1c32389d738c005c0df7a9d..db8c2ca2ce4cf2b3d2c0f5e824abc08cda220ed6 100644 (file)
--- a/drivers/char/tb0219.c
+++ b/drivers/char/tb0219.c
@@ -232,6 +232,7 @@ static ssize_t tanbac_tb0219_write(struct file *file, const char __user *data,
        return i;
 }
 
+/* No BKL needed here; no global resources accessed */
 static int tanbac_tb0219_open(struct inode *inode, struct file *file)
 {
        unsigned int minor;

diff --git a/drivers/char/vr41xx_giu.c b/drivers/char/vr41xx_giu.c
index e5ed09192be8675b615f6978dcf92f41a3dcf316..412937fdb958da364bba8cbe5686a16527b1d8de 100644 (file)
--- a/drivers/char/vr41xx_giu.c
+++ b/drivers/char/vr41xx_giu.c
@@ -543,6 +543,8 @@ static ssize_t gpio_write(struct file *file, const char __user *data,
        return i;
 }
 
+/* No BKL needed here; only global (giu_nr_pins) is only set
+   at probe time */
 static int gpio_open(struct inode *inode, struct file *file)
 {
        unsigned int pin;

diff --git a/drivers/infiniband/core/ucm.c b/drivers/infiniband/core/ucm.c
index d7a6881b571d990ec1fd47ba959126ac68a64b7e..3e6a8ff6d76cbc47019160a58a17e1e023f3ff26 100644 (file)
--- a/drivers/infiniband/core/ucm.c
+++ b/drivers/infiniband/core/ucm.c
@@ -1155,6 +1155,7 @@ static unsigned int ib_ucm_poll(struct file *filp,
        return mask;
 }
 
+/* No BKL needed here: no global resources used */
 static int ib_ucm_open(struct inode *inode, struct file *filp)
 {
        struct ib_ucm_file *file;

diff --git a/drivers/infiniband/hw/ipath/ipath_file_ops.c b/drivers/infiniband/hw/ipath/ipath_file_ops.c
index b472b15637f003da8b1a980a2d62206fb9c51eb3..e80cfbd4f3fd2d2536282a4d5e258ff8482b7155 100644 (file)
--- a/drivers/infiniband/hw/ipath/ipath_file_ops.c
+++ b/drivers/infiniband/hw/ipath/ipath_file_ops.c
@@ -1812,6 +1812,7 @@ done:
        return ret;
 }
 
+/* No BKL needed here */
 static int ipath_open(struct inode *in, struct file *fp)
 {
        /* The real work is performed later in ipath_assign_port() */

diff --git a/drivers/net/ppp_generic.c b/drivers/net/ppp_generic.c
index 1f4ca2b54a73370213d1ce162c5c048e00bfc732..dc8505062da7252d397787015c46c7f7d3e22805 100644 (file)
--- a/drivers/net/ppp_generic.c
+++ b/drivers/net/ppp_generic.c
@@ -351,6 +351,7 @@ static const int npindex_to_ethertype[NUM_NP] = {
  * Open instances of /dev/ppp can be in one of three states:
  * unattached, attached to a ppp unit, or attached to a ppp channel.
  */
+/* No BKL needed here */
 static int ppp_open(struct inode *inode, struct file *file)
 {
        /*

diff --git a/drivers/scsi/3w-9xxx.c b/drivers/scsi/3w-9xxx.c
index b31faeccb9cde4f0e15a762e38c777ba6a2ea976..2239d16fb9b568225df0fa5e0e26eaec4a2be5f7 100644 (file)
--- a/drivers/scsi/3w-9xxx.c
+++ b/drivers/scsi/3w-9xxx.c
@@ -862,6 +862,8 @@ out:
 } /* End twa_chrdev_ioctl() */
 
 /* This function handles open for the character device */
+/* NOTE that this function will race with remove; adding BKL
+   will not help. */
 static int twa_chrdev_open(struct inode *inode, struct file *file)
 {
        unsigned int minor_number;

diff --git a/drivers/scsi/3w-xxxx.c b/drivers/scsi/3w-xxxx.c
index 8c22329aa85e1585035127185c0597cb51a95827..bbff029536ea3dda3dfdd39f4f20734ded7b91c4 100644 (file)
--- a/drivers/scsi/3w-xxxx.c
+++ b/drivers/scsi/3w-xxxx.c
@@ -1027,6 +1027,8 @@ out:
 } /* End tw_chrdev_ioctl() */
 
 /* This function handles open for the character device */
+/* NOTE that this function races with remove - adding BKL
+   won't help */
 static int tw_chrdev_open(struct inode *inode, struct file *file)
 {
        unsigned int minor_number;

diff --git a/drivers/scsi/megaraid.c b/drivers/scsi/megaraid.c
index 18551aaf5e094e07612ddf028df0dc7f2a05d344..c9aa2c45a6992dc2ec65e5b86b6d8d3f7c9f0031 100644 (file)
--- a/drivers/scsi/megaraid.c
+++ b/drivers/scsi/megaraid.c
@@ -3272,8 +3272,9 @@ mega_init_scb(adapter_t *adapter)
  * @filep - unused
  *
  * Routines for the character/ioctl interface to the driver. Find out if this
- * is a valid open. If yes, increment the module use count so that it cannot
- * be unloaded.
+ * is a valid open. 
+ *
+ * No BKL needed here.
  */
 static int
 megadev_open (struct inode *inode, struct file *filep)

diff --git a/drivers/scsi/megaraid/megaraid_sas.c b/drivers/scsi/megaraid/megaraid_sas.c
index 7d84c8bbcf3fc1a55b8a9c04cbc65e2e05b33902..81374b7c555ce926a4be6321b0b95ec29eb39d4e 100644 (file)
--- a/drivers/scsi/megaraid/megaraid_sas.c
+++ b/drivers/scsi/megaraid/megaraid_sas.c
@@ -2860,6 +2860,7 @@ static void megasas_shutdown(struct pci_dev *pdev)
 
 /**
  * megasas_mgmt_open - char node "open" entry point
+ * No BKL is needed here.
  */
 static int megasas_mgmt_open(struct inode *inode, struct file *filep)
 {