2010-04-28 09:01:39

by Dan Carpenter

Subject: [patch] iwl: cleanup: remove unneeded error handling

This is just a cleanup and doesn't change how the code works.

debugfs_create_dir() and debugfs_create_file() return an error pointer
(-ENODEV) if CONFIG_DEBUG_FS is not enabled, otherwise if an error occurs
they return NULL. This is how they are implemented and what it says in
the DebugFS documentation. DebugFS can not be compiled as a module.

As a result, we only need to check for error pointers and particularly
-ENODEV one time to know that DebugFS is enabled. This patch keeps the
first check for error pointers and removes the rest.

The other reason for this patch, is that it silences some Smatch warnings.
Smatch sees the condition "(result != -ENODEV)" and assumes that it's
possible for "result" to equal -ENODEV. If it were possible it would lead
to an error pointer dereference. But since it's not, we can just remove
the check.

Signed-off-by: Dan Carpenter <[email protected]>

diff --git a/drivers/net/wireless/iwmc3200wifi/debugfs.c b/drivers/net/wireless/iwmc3200wifi/debugfs.c
index cbb81be..10eeeeb 100644
--- a/drivers/net/wireless/iwmc3200wifi/debugfs.c
+++ b/drivers/net/wireless/iwmc3200wifi/debugfs.c
@@ -438,40 +438,10 @@ int iwm_debugfs_init(struct iwm_priv *iwm)
snprintf(devdir, sizeof(devdir), "%s", wiphy_name(iwm_to_wiphy(iwm)));

iwm->dbg.devdir = debugfs_create_dir(devdir, iwm->dbg.rootdir);
- result = PTR_ERR(iwm->dbg.devdir);
- if (IS_ERR(iwm->dbg.devdir) && (result != -ENODEV)) {
- IWM_ERR(iwm, "Couldn't create devdir: %d\n", result);
- goto error;
- }
-
iwm->dbg.dbgdir = debugfs_create_dir("debug", iwm->dbg.devdir);
- result = PTR_ERR(iwm->dbg.dbgdir);
- if (IS_ERR(iwm->dbg.dbgdir) && (result != -ENODEV)) {
- IWM_ERR(iwm, "Couldn't create dbgdir: %d\n", result);
- goto error;
- }
-
iwm->dbg.rxdir = debugfs_create_dir("rx", iwm->dbg.devdir);
- result = PTR_ERR(iwm->dbg.rxdir);
- if (IS_ERR(iwm->dbg.rxdir) && (result != -ENODEV)) {
- IWM_ERR(iwm, "Couldn't create rx dir: %d\n", result);
- goto error;
- }
-
iwm->dbg.txdir = debugfs_create_dir("tx", iwm->dbg.devdir);
- result = PTR_ERR(iwm->dbg.txdir);
- if (IS_ERR(iwm->dbg.txdir) && (result != -ENODEV)) {
- IWM_ERR(iwm, "Couldn't create tx dir: %d\n", result);
- goto error;
- }
-
iwm->dbg.busdir = debugfs_create_dir("bus", iwm->dbg.devdir);
- result = PTR_ERR(iwm->dbg.busdir);
- if (IS_ERR(iwm->dbg.busdir) && (result != -ENODEV)) {
- IWM_ERR(iwm, "Couldn't create bus dir: %d\n", result);
- goto error;
- }
-
if (iwm->bus_ops->debugfs_init) {
result = iwm->bus_ops->debugfs_init(iwm, iwm->dbg.busdir);
if (result < 0) {
@@ -480,27 +450,15 @@ int iwm_debugfs_init(struct iwm_priv *iwm)
}
}

-
iwm->dbg.dbg_level = IWM_DL_NONE;
iwm->dbg.dbg_level_dentry =
debugfs_create_file("level", 0200, iwm->dbg.dbgdir, iwm,
&fops_iwm_dbg_level);
- result = PTR_ERR(iwm->dbg.dbg_level_dentry);
- if (IS_ERR(iwm->dbg.dbg_level_dentry) && (result != -ENODEV)) {
- IWM_ERR(iwm, "Couldn't create dbg_level: %d\n", result);
- goto error;
- }
-

iwm->dbg.dbg_modules = IWM_DM_DEFAULT;
iwm->dbg.dbg_modules_dentry =
debugfs_create_file("modules", 0200, iwm->dbg.dbgdir, iwm,
&fops_iwm_dbg_modules);
- result = PTR_ERR(iwm->dbg.dbg_modules_dentry);
- if (IS_ERR(iwm->dbg.dbg_modules_dentry) && (result != -ENODEV)) {
- IWM_ERR(iwm, "Couldn't create dbg_modules: %d\n", result);
- goto error;
- }

for (i = 0; i < __IWM_DM_NR; i++)
add_dbg_module(iwm->dbg, iwm_debug_module[i].name,
@@ -509,39 +467,18 @@ int iwm_debugfs_init(struct iwm_priv *iwm)
iwm->dbg.txq_dentry = debugfs_create_file("queues", 0200,
iwm->dbg.txdir, iwm,
&iwm_debugfs_txq_fops);
- result = PTR_ERR(iwm->dbg.txq_dentry);
- if (IS_ERR(iwm->dbg.txq_dentry) && (result != -ENODEV)) {
- IWM_ERR(iwm, "Couldn't create tx queue: %d\n", result);
- goto error;
- }

iwm->dbg.tx_credit_dentry = debugfs_create_file("credits", 0200,
iwm->dbg.txdir, iwm,
&iwm_debugfs_tx_credit_fops);
- result = PTR_ERR(iwm->dbg.tx_credit_dentry);
- if (IS_ERR(iwm->dbg.tx_credit_dentry) && (result != -ENODEV)) {
- IWM_ERR(iwm, "Couldn't create tx credit: %d\n", result);
- goto error;
- }

iwm->dbg.rx_ticket_dentry = debugfs_create_file("tickets", 0200,
iwm->dbg.rxdir, iwm,
&iwm_debugfs_rx_ticket_fops);
- result = PTR_ERR(iwm->dbg.rx_ticket_dentry);
- if (IS_ERR(iwm->dbg.rx_ticket_dentry) && (result != -ENODEV)) {
- IWM_ERR(iwm, "Couldn't create rx ticket: %d\n", result);
- goto error;
- }

iwm->dbg.fw_err_dentry = debugfs_create_file("last_fw_err", 0200,
iwm->dbg.dbgdir, iwm,
&iwm_debugfs_fw_err_fops);
- result = PTR_ERR(iwm->dbg.fw_err_dentry);
- if (IS_ERR(iwm->dbg.fw_err_dentry) && (result != -ENODEV)) {
- IWM_ERR(iwm, "Couldn't create last FW err: %d\n", result);
- goto error;
- }
-

return 0;

2010-04-29 02:15:10

by Zhu Yi

Subject: Re: [patch] iwl: cleanup: remove unneeded error handling

On Wed, 2010-04-28 at 17:01 +0800, Dan Carpenter wrote:
> This is just a cleanup and doesn't change how the code works.
>
> debugfs_create_dir() and debugfs_create_file() return an error pointer
> (-ENODEV) if CONFIG_DEBUG_FS is not enabled, otherwise if an error occurs
> they return NULL. This is how they are implemented and what it says in
> the DebugFS documentation. DebugFS can not be compiled as a module.
>
> As a result, we only need to check for error pointers and particularly
> -ENODEV one time to know that DebugFS is enabled. This patch keeps the
> first check for error pointers and removes the rest.
>
> The other reason for this patch, is that it silences some Smatch warnings.
> Smatch sees the condition "(result != -ENODEV)" and assumes that it's
> possible for "result" to equal -ENODEV. If it were possible it would lead
> to an error pointer dereference. But since it's not, we can just remove
> the check.
>
> Signed-off-by: Dan Carpenter <[email protected]>

Thanks. But looks like you missed the one in if_sdio_debugfs_init().

I don't think we even need to check -ENODEV ourselves because if
DEBUG_FS is not compiled in, all the debugfs utility functions will
become no-op.

Signed-off-by: Dan Carpenter <[email protected]>
Signed-off-by: Zhu Yi <[email protected]>

diff --git a/drivers/net/wireless/iwmc3200wifi/bus.h b/drivers/net/wireless/iwmc3200wifi/bus.h
index 836663e..62edd58 100644
--- a/drivers/net/wireless/iwmc3200wifi/bus.h
+++ b/drivers/net/wireless/iwmc3200wifi/bus.h
@@ -31,7 +31,7 @@ struct iwm_if_ops {
int (*disable)(struct iwm_priv *iwm);
int (*send_chunk)(struct iwm_priv *iwm, u8* buf, int count);

- int (*debugfs_init)(struct iwm_priv *iwm, struct dentry *parent_dir);
+ void (*debugfs_init)(struct iwm_priv *iwm, struct dentry *parent_dir);
void (*debugfs_exit)(struct iwm_priv *iwm);

const char *umac_name;
diff --git a/drivers/net/wireless/iwmc3200wifi/debug.h b/drivers/net/wireless/iwmc3200wifi/debug.h
index e35c9b6..f98bf12 100644
--- a/drivers/net/wireless/iwmc3200wifi/debug.h
+++ b/drivers/net/wireless/iwmc3200wifi/debug.h
@@ -113,10 +113,10 @@ struct iwm_debugfs {
};

#ifdef CONFIG_IWM_DEBUG
-int iwm_debugfs_init(struct iwm_priv *iwm);
+void iwm_debugfs_init(struct iwm_priv *iwm);
void iwm_debugfs_exit(struct iwm_priv *iwm);
#else
-static inline int iwm_debugfs_init(struct iwm_priv *iwm)
+static inline void iwm_debugfs_init(struct iwm_priv *iwm)
{
return 0;
}
diff --git a/drivers/net/wireless/iwmc3200wifi/debugfs.c b/drivers/net/wireless/iwmc3200wifi/debugfs.c
index 7244413..53b0b77 100644
--- a/drivers/net/wireless/iwmc3200wifi/debugfs.c
+++ b/drivers/net/wireless/iwmc3200wifi/debugfs.c
@@ -48,12 +48,11 @@ static struct {

#define add_dbg_module(dbg, name, id, initlevel) \
do { \
- struct dentry *d; \
dbg.dbg_module[id] = (initlevel); \
- d = debugfs_create_x8(name, 0600, dbg.dbgdir, \
- &(dbg.dbg_module[id])); \
- if (!IS_ERR(d)) \
- dbg.dbg_module_dentries[id] = d; \
+ dbg.dbg_module_dentries[id] = \
+ debugfs_create_x8(name, 0600, \
+ dbg.dbgdir, \
+ &(dbg.dbg_module[id])); \
} while (0)

static int iwm_debugfs_u32_read(void *data, u64 *val)
@@ -423,89 +422,29 @@ static const struct file_operations iwm_debugfs_fw_err_fops = {
.read = iwm_debugfs_fw_err_read,
};

-int iwm_debugfs_init(struct iwm_priv *iwm)
+void iwm_debugfs_init(struct iwm_priv *iwm)
{
- int i, result;
- char devdir[16];
+ int i;

iwm->dbg.rootdir = debugfs_create_dir(KBUILD_MODNAME, NULL);
- result = PTR_ERR(iwm->dbg.rootdir);
- if (!result || IS_ERR(iwm->dbg.rootdir)) {
- if (result == -ENODEV) {
- IWM_ERR(iwm, "DebugFS (CONFIG_DEBUG_FS) not "
- "enabled in kernel config\n");
- result = 0; /* No debugfs support */
- }
- IWM_ERR(iwm, "Couldn't create rootdir: %d\n", result);
- goto error;
- }
-
- snprintf(devdir, sizeof(devdir), "%s", wiphy_name(iwm_to_wiphy(iwm)));
-
- iwm->dbg.devdir = debugfs_create_dir(devdir, iwm->dbg.rootdir);
- result = PTR_ERR(iwm->dbg.devdir);
- if (IS_ERR(iwm->dbg.devdir) && (result != -ENODEV)) {
- IWM_ERR(iwm, "Couldn't create devdir: %d\n", result);
- goto error;
- }
-
+ iwm->dbg.devdir = debugfs_create_dir(wiphy_name(iwm_to_wiphy(iwm)),
+ iwm->dbg.rootdir);
iwm->dbg.dbgdir = debugfs_create_dir("debug", iwm->dbg.devdir);
- result = PTR_ERR(iwm->dbg.dbgdir);
- if (IS_ERR(iwm->dbg.dbgdir) && (result != -ENODEV)) {
- IWM_ERR(iwm, "Couldn't create dbgdir: %d\n", result);
- goto error;
- }
-
iwm->dbg.rxdir = debugfs_create_dir("rx", iwm->dbg.devdir);
- result = PTR_ERR(iwm->dbg.rxdir);
- if (IS_ERR(iwm->dbg.rxdir) && (result != -ENODEV)) {
- IWM_ERR(iwm, "Couldn't create rx dir: %d\n", result);
- goto error;
- }
-
iwm->dbg.txdir = debugfs_create_dir("tx", iwm->dbg.devdir);
- result = PTR_ERR(iwm->dbg.txdir);
- if (IS_ERR(iwm->dbg.txdir) && (result != -ENODEV)) {
- IWM_ERR(iwm, "Couldn't create tx dir: %d\n", result);
- goto error;
- }
-
iwm->dbg.busdir = debugfs_create_dir("bus", iwm->dbg.devdir);
- result = PTR_ERR(iwm->dbg.busdir);
- if (IS_ERR(iwm->dbg.busdir) && (result != -ENODEV)) {
- IWM_ERR(iwm, "Couldn't create bus dir: %d\n", result);
- goto error;
- }
-
- if (iwm->bus_ops->debugfs_init) {
- result = iwm->bus_ops->debugfs_init(iwm, iwm->dbg.busdir);
- if (result < 0) {
- IWM_ERR(iwm, "Couldn't create bus entry: %d\n", result);
- goto error;
- }
- }
-
+ if (iwm->bus_ops->debugfs_init)
+ iwm->bus_ops->debugfs_init(iwm, iwm->dbg.busdir);

iwm->dbg.dbg_level = IWM_DL_NONE;
iwm->dbg.dbg_level_dentry =
debugfs_create_file("level", 0200, iwm->dbg.dbgdir, iwm,
&fops_iwm_dbg_level);
- result = PTR_ERR(iwm->dbg.dbg_level_dentry);
- if (IS_ERR(iwm->dbg.dbg_level_dentry) && (result != -ENODEV)) {
- IWM_ERR(iwm, "Couldn't create dbg_level: %d\n", result);
- goto error;
- }
-

iwm->dbg.dbg_modules = IWM_DM_DEFAULT;
iwm->dbg.dbg_modules_dentry =
debugfs_create_file("modules", 0200, iwm->dbg.dbgdir, iwm,
&fops_iwm_dbg_modules);
- result = PTR_ERR(iwm->dbg.dbg_modules_dentry);
- if (IS_ERR(iwm->dbg.dbg_modules_dentry) && (result != -ENODEV)) {
- IWM_ERR(iwm, "Couldn't create dbg_modules: %d\n", result);
- goto error;
- }

for (i = 0; i < __IWM_DM_NR; i++)
add_dbg_module(iwm->dbg, iwm_debug_module[i].name,
@@ -514,44 +453,15 @@ int iwm_debugfs_init(struct iwm_priv *iwm)
iwm->dbg.txq_dentry = debugfs_create_file("queues", 0200,
iwm->dbg.txdir, iwm,
&iwm_debugfs_txq_fops);
- result = PTR_ERR(iwm->dbg.txq_dentry);
- if (IS_ERR(iwm->dbg.txq_dentry) && (result != -ENODEV)) {
- IWM_ERR(iwm, "Couldn't create tx queue: %d\n", result);
- goto error;
- }
-
iwm->dbg.tx_credit_dentry = debugfs_create_file("credits", 0200,
iwm->dbg.txdir, iwm,
&iwm_debugfs_tx_credit_fops);
- result = PTR_ERR(iwm->dbg.tx_credit_dentry);
- if (IS_ERR(iwm->dbg.tx_credit_dentry) && (result != -ENODEV)) {
- IWM_ERR(iwm, "Couldn't create tx credit: %d\n", result);
- goto error;
- }
-
iwm->dbg.rx_ticket_dentry = debugfs_create_file("tickets", 0200,
iwm->dbg.rxdir, iwm,
&iwm_debugfs_rx_ticket_fops);
- result = PTR_ERR(iwm->dbg.rx_ticket_dentry);
- if (IS_ERR(iwm->dbg.rx_ticket_dentry) && (result != -ENODEV)) {
- IWM_ERR(iwm, "Couldn't create rx ticket: %d\n", result);
- goto error;
- }
-
iwm->dbg.fw_err_dentry = debugfs_create_file("last_fw_err", 0200,
iwm->dbg.dbgdir, iwm,
&iwm_debugfs_fw_err_fops);
- result = PTR_ERR(iwm->dbg.fw_err_dentry);
- if (IS_ERR(iwm->dbg.fw_err_dentry) && (result != -ENODEV)) {
- IWM_ERR(iwm, "Couldn't create last FW err: %d\n", result);
- goto error;
- }
-
-
- return 0;
-
- error:
- return result;
}

void iwm_debugfs_exit(struct iwm_priv *iwm)
diff --git a/drivers/net/wireless/iwmc3200wifi/sdio.c b/drivers/net/wireless/iwmc3200wifi/sdio.c
index 1eafd6d..1acea37 100644
--- a/drivers/net/wireless/iwmc3200wifi/sdio.c
+++ b/drivers/net/wireless/iwmc3200wifi/sdio.c
@@ -366,21 +366,13 @@ static const struct file_operations iwm_debugfs_sdio_fops = {
.read = iwm_debugfs_sdio_read,
};

-static int if_sdio_debugfs_init(struct iwm_priv *iwm, struct dentry *parent_dir)
+static void if_sdio_debugfs_init(struct iwm_priv *iwm, struct dentry *parent_dir)
{
- int result;
struct iwm_sdio_priv *hw = iwm_to_if_sdio(iwm);

hw->cccr_dentry = debugfs_create_file("cccr", 0200,
parent_dir, iwm,
&iwm_debugfs_sdio_fops);
- result = PTR_ERR(hw->cccr_dentry);
- if (IS_ERR(hw->cccr_dentry) && (result != -ENODEV)) {
- IWM_ERR(iwm, "Couldn't create CCCR entry: %d\n", result);
- return result;
- }
-
- return 0;
}

static void if_sdio_debugfs_exit(struct iwm_priv *iwm)
@@ -440,11 +432,7 @@ static int iwm_sdio_probe(struct sdio_func *func,
hw = iwm_private(iwm);
hw->iwm = iwm;

- ret = iwm_debugfs_init(iwm);
- if (ret < 0) {
- IWM_ERR(iwm, "Debugfs registration failed\n");
- goto if_free;
- }
+ iwm_debugfs_init(iwm);

sdio_set_drvdata(func, hw);

@@ -473,7 +461,6 @@ static int iwm_sdio_probe(struct sdio_func *func,
destroy_workqueue(hw->isr_wq);
debugfs_exit:
iwm_debugfs_exit(iwm);
- if_free:
iwm_if_free(iwm);
return ret;
}

2010-04-30 17:32:30

by Dan Carpenter

Subject: Re: [patch] iwl: cleanup: remove unneeded error handling

On Thu, Apr 29, 2010 at 10:12:14AM +0800, Zhu Yi wrote:
>
> Thanks. But looks like you missed the one in if_sdio_debugfs_init().
>

Yup.

> I don't think we even need to check -ENODEV ourselves because if
> DEBUG_FS is not compiled in, all the debugfs utility functions will
> become no-op.
>

Good point.

> Signed-off-by: Dan Carpenter <[email protected]>

Probably this could get changed to just "Reported-by" but I'm happy to
take credit for other peoples work. :)

> Signed-off-by: Zhu Yi <[email protected]>
>

Acked-by: Dan Carpenter <[email protected]>

regards,
dan carpenter