[PATCH v2 4/4] PCI: remove assignement in non straight forward if condition

[PATCH v2 4/4] PCI: remove assignement in non straight forward if condition

[Quentin Lambert]

The modifications effectively change the value of len_tmp
in the case where the first condition is not met.

Signed-off-by: Quentin Lambert <lambert.quentin@gmail.com>
---
 drivers/pci/hotplug/ibmphp_res.c | 13 +++++++++----
 drivers/pci/pci.c                |  6 +++++-
 drivers/pci/slot.c               | 12 ++++++++++--
 3 files changed, 24 insertions(+), 7 deletions(-)

diff --git a/drivers/pci/hotplug/ibmphp_res.c b/drivers/pci/hotplug/ibmphp_res.c
index e07f34e..7066c34 100644
--- a/drivers/pci/hotplug/ibmphp_res.c
+++ b/drivers/pci/hotplug/ibmphp_res.c
@@ -1044,7 +1044,9 @@ int ibmphp_check_resource (struct resource_node *res, u8 bridge)
 		/* found our range */
 		if (!res_prev) {
 			/* first time in the loop */
-			if ((res_cur->start != range->start) && ((len_tmp = res_cur->start - 1 - range->start) >= res->len)) {
+			len_tmp = res_cur->start - 1 - range->start;
+
+			if ((res_cur->start != range->start) && (len_tmp >= res->len)) {
 				debug ("len_tmp = %x\n", len_tmp);
 
 				if ((len_tmp < len_cur) || (len_cur == 0)) {
@@ -1084,7 +1086,9 @@ int ibmphp_check_resource (struct resource_node *res, u8 bridge)
 		}
 		if (!res_cur->next) {
 			/* last device on the range */
-			if ((range->end != res_cur->end) && ((len_tmp = range->end - (res_cur->end + 1)) >= res->len)) {
+			len_tmp = range->end - (res_cur->end + 1);
+
+			if ((range->end != res_cur->end) && (len_tmp >= res->len)) {
 				debug ("len_tmp = %x\n", len_tmp);
 				if ((len_tmp < len_cur) || (len_cur == 0)) {
 
@@ -1123,8 +1127,9 @@ int ibmphp_check_resource (struct resource_node *res, u8 bridge)
 		if (res_prev) {
 			if (res_prev->rangeno != res_cur->rangeno) {
 				/* 1st device on this range */
-				if ((res_cur->start != range->start) &&
-					((len_tmp = res_cur->start - 1 - range->start) >= res->len)) {
+				len_tmp = res_cur->start - 1 - range->start;
+
+				if ((res_cur->start != range->start) &&	(len_tmp >= res->len)) {
 					if ((len_tmp < len_cur) || (len_cur == 0)) {
 						if ((range->start % tmp_divide) == 0) {
 							/* just perfect, starting address is divisible by length */
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 8b63a5b..4c3ef21 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -4434,9 +4434,13 @@ static int __init pci_setup(char *str)
 {
 	while (str) {
 		char *k = strchr(str, ',');
+		char tmp = *str;
+
 		if (k)
 			*k++ = 0;
-		if (*str && (str = pcibios_setup(str)) && *str) {
+
+		str = pcibios_setup(str);
+		if (tmp && str && *str) {
 			if (!strcmp(str, "nomsi")) {
 				pci_no_msi();
 			} else if (!strcmp(str, "noaer")) {
diff --git a/drivers/pci/slot.c b/drivers/pci/slot.c
index 396c200..22d20db 100644
--- a/drivers/pci/slot.c
+++ b/drivers/pci/slot.c
@@ -265,8 +265,16 @@ struct pci_slot *pci_create_slot(struct pci_bus *parent, int slot_nr,
 	slot = get_slot(parent, slot_nr);
 	if (slot) {
 		if (hotplug) {
-			if ((err = slot->hotplug ? -EBUSY : 0)
-			     || (err = rename_slot(slot, name))) {
+			err = slot->hotplug ? -EBUSY : 0;
+			if (err)
+				goto hotplugerror;
+
+			err = rename_slot(slot, name);
+			if (err)
+				goto hotplugerror;
+
+			if (0) {
+hotplugerror:
 				kobject_put(&slot->kobj);
 				slot = NULL;
 				goto err;
-- 
1.9.1

Re: [PATCH v2 4/4] PCI: remove assignement in non straight forward if condition

[Bjorn Helgaas]

On Sun, Sep 07, 2014 at 08:04:28PM +0200, Quentin Lambert wrote:
> The modifications effectively change the value of len_tmp
> in the case where the first condition is not met.
> 
> Signed-off-by: Quentin Lambert <lambert.quentin@gmail.com>
> ---
>  drivers/pci/hotplug/ibmphp_res.c | 13 +++++++++----
>  drivers/pci/pci.c                |  6 +++++-
>  drivers/pci/slot.c               | 12 ++++++++++--
>  3 files changed, 24 insertions(+), 7 deletions(-)
> ...

> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> index 8b63a5b..4c3ef21 100644
> --- a/drivers/pci/pci.c
> +++ b/drivers/pci/pci.c
> @@ -4434,9 +4434,13 @@ static int __init pci_setup(char *str)
>  {
>  	while (str) {
>  		char *k = strchr(str, ',');
> +		char tmp = *str;
> +
>  		if (k)
>  			*k++ = 0;
> -		if (*str && (str = pcibios_setup(str)) && *str) {
> +
> +		str = pcibios_setup(str);
> +		if (tmp && str && *str) {

I dropped this change  because I don't think the replacement is quite
equivalent.  Previously, we only called pcibios_setup() if "*str".  The new
code calls it even if "!*str".

>  			if (!strcmp(str, "nomsi")) {
>  				pci_no_msi();
>  			} else if (!strcmp(str, "noaer")) {
> diff --git a/drivers/pci/slot.c b/drivers/pci/slot.c
> index 396c200..22d20db 100644
> --- a/drivers/pci/slot.c
> +++ b/drivers/pci/slot.c
> @@ -265,8 +265,16 @@ struct pci_slot *pci_create_slot(struct pci_bus *parent, int slot_nr,
>  	slot = get_slot(parent, slot_nr);
>  	if (slot) {
>  		if (hotplug) {
> -			if ((err = slot->hotplug ? -EBUSY : 0)
> -			     || (err = rename_slot(slot, name))) {
> +			err = slot->hotplug ? -EBUSY : 0;
> +			if (err)
> +				goto hotplugerror;
> +
> +			err = rename_slot(slot, name);
> +			if (err)
> +				goto hotplugerror;
> +
> +			if (0) {
> +hotplugerror:
>  				kobject_put(&slot->kobj);
>  				slot = NULL;
>  				goto err;

And I dropped this one because the code is too ugly.  Granted, the
original is probably even uglier, but if we're going to change it, I'm
going to hold out for a prettier restructuring.

Bjorn