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Message-ID: <20220603201407.GA688883-robh@kernel.org>
Date: Fri, 3 Jun 2022 15:14:07 -0500
From: Rob Herring <robh@...nel.org>
To: Clément Léger <clement.leger@...tlin.com>
Cc: Michael Ellerman <mpe@...erman.id.au>,
Benjamin Herrenschmidt <benh@...nel.crashing.org>,
Paul Mackerras <paulus@...ba.org>,
Frank Rowand <frowand.list@...il.com>,
Nathan Lynch <nathanl@...ux.ibm.com>,
Laurent Dufour <ldufour@...ux.ibm.com>,
Daniel Henrique Barboza <danielhb413@...il.com>,
David Gibson <david@...son.dropbear.id.au>,
Andrew Morton <akpm@...ux-foundation.org>,
David Hildenbrand <david@...hat.com>,
Ohhoon Kwon <ohoono.kwon@...sung.com>,
"Aneesh Kumar K.V" <aneesh.kumar@...ux.ibm.com>,
YueHaibing <yuehaibing@...wei.com>,
linuxppc-dev@...ts.ozlabs.org, linux-kernel@...r.kernel.org,
devicetree@...r.kernel.org,
Allan Nielsen <allan.nielsen@...rochip.com>,
Horatiu Vultur <horatiu.vultur@...rochip.com>,
Steen Hegelund <steen.hegelund@...rochip.com>,
Thomas Petazzoni <thomas.petazzoni@...tlin.com>,
Bjorn Helgaas <helgaas@...nel.org>,
Lizhi Hou <lizhi.hou@...inx.com>
Subject: Re: [PATCH v2 4/4] powerpc/pseries: use of_property_alloc/free() and
of_node_alloc()
On Wed, Jun 01, 2022 at 10:18:01AM +0200, Clément Léger wrote:
> Use of_property_alloc/free() and of_node_alloc() to create and free
> device-tree nodes and properties.
>
> Signed-off-by: Clément Léger <clement.leger@...tlin.com>
> ---
> arch/powerpc/platforms/pseries/dlpar.c | 51 +++----------------
> .../platforms/pseries/hotplug-memory.c | 21 +-------
> arch/powerpc/platforms/pseries/reconfig.c | 45 +++++-----------
> 3 files changed, 21 insertions(+), 96 deletions(-)
>
> diff --git a/arch/powerpc/platforms/pseries/dlpar.c b/arch/powerpc/platforms/pseries/dlpar.c
> index 498d6efcb5ae..5a04566e98a4 100644
> --- a/arch/powerpc/platforms/pseries/dlpar.c
> +++ b/arch/powerpc/platforms/pseries/dlpar.c
> @@ -38,61 +38,25 @@ struct cc_workarea {
> __be32 prop_offset;
> };
>
> -void dlpar_free_cc_property(struct property *prop)
> -{
> - kfree(prop->name);
> - kfree(prop->value);
> - kfree(prop);
> -}
> -
> static struct property *dlpar_parse_cc_property(struct cc_workarea *ccwa)
> {
> - struct property *prop;
> - char *name;
> - char *value;
> -
> - prop = kzalloc(sizeof(*prop), GFP_KERNEL);
> - if (!prop)
> - return NULL;
> + int length;
> + char *name, *value;
>
> name = (char *)ccwa + be32_to_cpu(ccwa->name_offset);
> - prop->name = kstrdup(name, GFP_KERNEL);
> - if (!prop->name) {
> - dlpar_free_cc_property(prop);
> - return NULL;
> - }
> -
> - prop->length = be32_to_cpu(ccwa->prop_length);
> + length = be32_to_cpu(ccwa->prop_length);
> value = (char *)ccwa + be32_to_cpu(ccwa->prop_offset);
> - prop->value = kmemdup(value, prop->length, GFP_KERNEL);
> - if (!prop->value) {
> - dlpar_free_cc_property(prop);
> - return NULL;
> - }
>
> - return prop;
> + return of_property_alloc(name, value, length, GFP_KERNEL);
> }
>
> static struct device_node *dlpar_parse_cc_node(struct cc_workarea *ccwa)
> {
> - struct device_node *dn;
> const char *name;
>
> - dn = kzalloc(sizeof(*dn), GFP_KERNEL);
> - if (!dn)
> - return NULL;
> -
> name = (const char *)ccwa + be32_to_cpu(ccwa->name_offset);
> - dn->full_name = kstrdup(name, GFP_KERNEL);
> - if (!dn->full_name) {
> - kfree(dn);
> - return NULL;
> - }
>
> - of_node_set_flag(dn, OF_DYNAMIC);
> - of_node_init(dn);
> -
> - return dn;
> + return of_node_alloc(name, GFP_KERNEL);
Do you have any need for different flags? I can't really see a need for
atomic or dma allocs or ???, so drop it I think.
> }
>
> static void dlpar_free_one_cc_node(struct device_node *dn)
> @@ -102,11 +66,10 @@ static void dlpar_free_one_cc_node(struct device_node *dn)
> while (dn->properties) {
> prop = dn->properties;
> dn->properties = prop->next;
> - dlpar_free_cc_property(prop);
> + of_property_free(prop);
We should be able to just put the node and all the properties already
attached will be freed.
Looking at the history of this code, it originally did the kref_init
much later in dlpar_attach_node(). So there was a window of allocating
the node and adding properties where you'd need to manually free
everything. Now that the node is referenced from the start, a put should
free everything.
> }
>
> - kfree(dn->full_name);
> - kfree(dn);
> + of_node_put(dn);
> }
>
> void dlpar_free_cc_nodes(struct device_node *dn)
> diff --git a/arch/powerpc/platforms/pseries/hotplug-memory.c b/arch/powerpc/platforms/pseries/hotplug-memory.c
> index 2e3a317722a8..2ddf2a0ba048 100644
> --- a/arch/powerpc/platforms/pseries/hotplug-memory.c
> +++ b/arch/powerpc/platforms/pseries/hotplug-memory.c
> @@ -69,33 +69,16 @@ unsigned long pseries_memory_block_size(void)
> return memblock_size;
> }
>
> -static void dlpar_free_property(struct property *prop)
> -{
> - kfree(prop->name);
> - kfree(prop->value);
> - kfree(prop);
> -}
> -
> static struct property *dlpar_clone_property(struct property *prop,
> u32 prop_size)
> {
> - struct property *new_prop;
> -
> - new_prop = kzalloc(sizeof(*new_prop), GFP_KERNEL);
> + struct property *new_prop = of_property_alloc(prop->name, NULL,
> + prop_size, GFP_KERNEL);
> if (!new_prop)
> return NULL;
>
> - new_prop->name = kstrdup(prop->name, GFP_KERNEL);
> - new_prop->value = kzalloc(prop_size, GFP_KERNEL);
> - if (!new_prop->name || !new_prop->value) {
> - dlpar_free_property(new_prop);
> - return NULL;
> - }
> -
> memcpy(new_prop->value, prop->value, prop->length);
> - new_prop->length = prop_size;
>
> - of_property_set_flag(new_prop, OF_DYNAMIC);
> return new_prop;
> }
>
> diff --git a/arch/powerpc/platforms/pseries/reconfig.c b/arch/powerpc/platforms/pseries/reconfig.c
> index cad7a0c93117..f1a364995e82 100644
> --- a/arch/powerpc/platforms/pseries/reconfig.c
> +++ b/arch/powerpc/platforms/pseries/reconfig.c
> @@ -24,17 +24,9 @@ static int pSeries_reconfig_add_node(const char *path, struct property *proplist
> struct device_node *np;
> int err = -ENOMEM;
>
> - np = kzalloc(sizeof(*np), GFP_KERNEL);
> + np = of_node_alloc(kbasename(path), GFP_KERNEL);
> if (!np)
> - goto out_err;
> -
> - np->full_name = kstrdup(kbasename(path), GFP_KERNEL);
> - if (!np->full_name)
> - goto out_err;
> -
> - np->properties = proplist;
> - of_node_set_flag(np, OF_DYNAMIC);
> - of_node_init(np);
> + return -ENOMEM;
>
> np->parent = pseries_of_derive_parent(path);
> if (IS_ERR(np->parent)) {
> @@ -55,8 +47,7 @@ static int pSeries_reconfig_add_node(const char *path, struct property *proplist
> out_err:
> if (np) {
> of_node_put(np->parent);
> - kfree(np->full_name);
> - kfree(np);
> + of_node_put(np);
> }
> return err;
> }
> @@ -91,9 +82,7 @@ static void release_prop_list(const struct property *prop)
> struct property *next;
> for (; prop; prop = next) {
> next = prop->next;
> - kfree(prop->name);
> - kfree(prop->value);
> - kfree(prop);
> + of_property_free(prop);
Looks like you need this because code does: alloc properties, alloc
node, add properties, attach node. It would need to be refactored to
alloc the node first, but that's a bit more complex needing someone to
test on pSeries.
> }
>
> }
> @@ -167,27 +156,17 @@ static char * parse_next_property(char *buf, char *end, char **name, int *length
> static struct property *new_property(const char *name, const int length,
> const unsigned char *value, struct property *last)
> {
> - struct property *new = kzalloc(sizeof(*new), GFP_KERNEL);
> + struct property *prop;
>
> - if (!new)
> + prop = of_property_alloc(name, NULL, length + 1, GFP_KERNEL);
> + if (!prop)
> return NULL;
>
> - if (!(new->name = kstrdup(name, GFP_KERNEL)))
> - goto cleanup;
> - if (!(new->value = kmalloc(length + 1, GFP_KERNEL)))
> - goto cleanup;
> -
> - memcpy(new->value, value, length);
> - *(((char *)new->value) + length) = 0;
> - new->length = length;
> - new->next = last;
> - return new;
> -
> -cleanup:
> - kfree(new->name);
> - kfree(new->value);
> - kfree(new);
> - return NULL;
> + memcpy(prop->value, value, length);
> + *(((char *)prop->value) + length) = 0;
Looks to me like this could be avoided with this change:
diff --git a/arch/powerpc/platforms/pseries/reconfig.c b/arch/powerpc/platforms/pseries/reconfig.c
index cad7a0c93117..614753fc5f27 100644
--- a/arch/powerpc/platforms/pseries/reconfig.c
+++ b/arch/powerpc/platforms/pseries/reconfig.c
@@ -148,7 +148,7 @@ static char * parse_next_property(char *buf, char *end, char **name, int *length
/* now we're on the value */
*value = tmp;
tmp += *length;
- if (tmp > end) {
+ if (tmp >= end) {
printk(KERN_ERR "property parse failed in %s at line %d\n",
__func__, __LINE__);
return NULL;
@@ -158,6 +158,7 @@ static char * parse_next_property(char *buf, char *end, char **name, int *length
__func__, __LINE__);
return NULL;
}
+ *tmp = '\0';
tmp++;
/* and now we should be on the next name, or the end */
Based on the comments, 'buf' should be nul terminated, so I would think
that tmp == end would be an error. But I really don't know.
Really need some pSeries people to comment on all this.
Another option is if value is NULL, then of_property_alloc() should
ensure the buffer is zeroed. Then you just need the memcpy.
Rob
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