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Message-Id: <1335194809-25321-1-git-send-email-mchehab@redhat.com>
Date: Mon, 23 Apr 2012 15:26:49 +0000
From: Mauro Carvalho Chehab <mchehab@...hat.com>
To: unlisted-recipients:; (no To-header on input)
Cc: Mauro Carvalho Chehab <mchehab@...hat.com>,
Linux Edac Mailing List <linux-edac@...r.kernel.org>,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
Aristeu Rozanski <arozansk@...hat.com>,
Doug Thompson <norsk5@...oo.com>
Subject: [PATCH] edac: rewrite edac_align_ptr()
The edac_align_ptr() function is used to prepare data for a single
memory allocation kzalloc() call. It counts how many bytes are needed
by some data structure.
Using it as-is is not that trivial, as the quantity of memory elements
reserved is not there, but, instead, it is on a next call.
In order to avoid mistakes when using it, move the number of allocated
elements into it, making easier to use it.
Reviewed-by: Borislav Petkov <bp@...64.org>
Cc: Aristeu Rozanski <arozansk@...hat.com>
Cc: Doug Thompson <norsk5@...oo.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@...hat.com>
---
v15: Fixes some comments and rename the name one var at edac_align_ptr(),
in order to improve the code readability, as per Borislav's review.
drivers/edac/edac_device.c | 27 +++++++++++----------------
drivers/edac/edac_mc.c | 44 +++++++++++++++++++++++++++++++++-----------
drivers/edac/edac_module.h | 2 +-
drivers/edac/edac_pci.c | 6 +++---
4 files changed, 48 insertions(+), 31 deletions(-)
diff --git a/drivers/edac/edac_device.c b/drivers/edac/edac_device.c
index 4b15459..cb397d9 100644
--- a/drivers/edac/edac_device.c
+++ b/drivers/edac/edac_device.c
@@ -79,7 +79,7 @@ struct edac_device_ctl_info *edac_device_alloc_ctl_info(
unsigned total_size;
unsigned count;
unsigned instance, block, attr;
- void *pvt;
+ void *pvt, *p;
int err;
debugf4("%s() instances=%d blocks=%d\n",
@@ -92,35 +92,30 @@ struct edac_device_ctl_info *edac_device_alloc_ctl_info(
* to be at least as stringent as what the compiler would
* provide if we could simply hardcode everything into a single struct.
*/
- dev_ctl = (struct edac_device_ctl_info *)NULL;
+ p = NULL;
+ dev_ctl = edac_align_ptr(&p, sizeof(*dev_ctl), 1);
/* Calc the 'end' offset past end of ONE ctl_info structure
* which will become the start of the 'instance' array
*/
- dev_inst = edac_align_ptr(&dev_ctl[1], sizeof(*dev_inst));
+ dev_inst = edac_align_ptr(&p, sizeof(*dev_inst), nr_instances);
/* Calc the 'end' offset past the instance array within the ctl_info
* which will become the start of the block array
*/
- dev_blk = edac_align_ptr(&dev_inst[nr_instances], sizeof(*dev_blk));
+ count = nr_instances * nr_blocks;
+ dev_blk = edac_align_ptr(&p, sizeof(*dev_blk), count);
/* Calc the 'end' offset past the dev_blk array
* which will become the start of the attrib array, if any.
*/
- count = nr_instances * nr_blocks;
- dev_attrib = edac_align_ptr(&dev_blk[count], sizeof(*dev_attrib));
-
- /* Check for case of when an attribute array is specified */
- if (nr_attrib > 0) {
- /* calc how many nr_attrib we need */
+ /* calc how many nr_attrib we need */
+ if (nr_attrib > 0)
count *= nr_attrib;
+ dev_attrib = edac_align_ptr(&p, sizeof(*dev_attrib), count);
- /* Calc the 'end' offset past the attributes array */
- pvt = edac_align_ptr(&dev_attrib[count], sz_private);
- } else {
- /* no attribute array specificed */
- pvt = edac_align_ptr(dev_attrib, sz_private);
- }
+ /* Calc the 'end' offset past the attributes array */
+ pvt = edac_align_ptr(&p, sz_private, 1);
/* 'pvt' now points to where the private data area is.
* At this point 'pvt' (like dev_inst,dev_blk and dev_attrib)
diff --git a/drivers/edac/edac_mc.c b/drivers/edac/edac_mc.c
index ffedae9..6ec967a 100644
--- a/drivers/edac/edac_mc.c
+++ b/drivers/edac/edac_mc.c
@@ -101,18 +101,37 @@ const char *edac_mem_types[] = {
};
EXPORT_SYMBOL_GPL(edac_mem_types);
-/* 'ptr' points to a possibly unaligned item X such that sizeof(X) is 'size'.
- * Adjust 'ptr' so that its alignment is at least as stringent as what the
- * compiler would provide for X and return the aligned result.
+/**
+ * edac_align_ptr - Prepares the pointer offsets for a single-shot allocation
+ * @p: pointer to a pointer with the memory offset to be used. At
+ * return, this will be incremented to point to the next offset
+ * @size: Size of the data structure to be reserved
+ * @n_elems: Number of elements that should be reserved
*
* If 'size' is a constant, the compiler will optimize this whole function
- * down to either a no-op or the addition of a constant to the value of 'ptr'.
+ * down to either a no-op or the addition of a constant to the value of '*p'.
+ *
+ * The 'p' pointer is absolutely needed to keep the proper advancing
+ * further in memory to the proper offsets when allocating the struct along
+ * with its embedded structs, as edac_device_alloc_ctl_info() does it
+ * above, for example.
+ *
+ * At return, the pointer 'p' will be incremented to be used on a next call
+ * to this function.
*/
-void *edac_align_ptr(void *ptr, unsigned size)
+void *edac_align_ptr(void **p, unsigned size, int n_elems)
{
unsigned align, r;
+ void *ptr = *p;
- /* Here we assume that the alignment of a "long long" is the most
+ *p += size * n_elems;
+
+ /*
+ * 'p' can possibly be an unaligned item X such that sizeof(X) is
+ * 'size'. Adjust 'p' so that its alignment is at least as
+ * stringent as what the compiler would provide for X and return
+ * the aligned result.
+ * Here we assume that the alignment of a "long long" is the most
* stringent alignment that the compiler will ever provide by default.
* As far as I know, this is a reasonable assumption.
*/
@@ -132,6 +151,8 @@ void *edac_align_ptr(void *ptr, unsigned size)
if (r == 0)
return (char *)ptr;
+ *p += align - r;
+
return (void *)(((unsigned long)ptr) + align - r);
}
@@ -154,6 +175,7 @@ void *edac_align_ptr(void *ptr, unsigned size)
struct mem_ctl_info *edac_mc_alloc(unsigned sz_pvt, unsigned nr_csrows,
unsigned nr_chans, int edac_index)
{
+ void *ptr = NULL;
struct mem_ctl_info *mci;
struct csrow_info *csi, *csrow;
struct rank_info *chi, *chp, *chan;
@@ -168,11 +190,11 @@ struct mem_ctl_info *edac_mc_alloc(unsigned sz_pvt, unsigned nr_csrows,
* stringent as what the compiler would provide if we could simply
* hardcode everything into a single struct.
*/
- mci = (struct mem_ctl_info *)0;
- csi = edac_align_ptr(&mci[1], sizeof(*csi));
- chi = edac_align_ptr(&csi[nr_csrows], sizeof(*chi));
- dimm = edac_align_ptr(&chi[nr_chans * nr_csrows], sizeof(*dimm));
- pvt = edac_align_ptr(&dimm[nr_chans * nr_csrows], sz_pvt);
+ mci = edac_align_ptr(&ptr, sizeof(*mci), 1);
+ csi = edac_align_ptr(&ptr, sizeof(*csi), nr_csrows);
+ chi = edac_align_ptr(&ptr, sizeof(*chi), nr_csrows * nr_chans);
+ dimm = edac_align_ptr(&ptr, sizeof(*dimm), nr_csrows * nr_chans);
+ pvt = edac_align_ptr(&ptr, sz_pvt, 1);
size = ((unsigned long)pvt) + sz_pvt;
mci = kzalloc(size, GFP_KERNEL);
diff --git a/drivers/edac/edac_module.h b/drivers/edac/edac_module.h
index 00f81b4..0ea7d14 100644
--- a/drivers/edac/edac_module.h
+++ b/drivers/edac/edac_module.h
@@ -50,7 +50,7 @@ extern void edac_device_reset_delay_period(struct edac_device_ctl_info
*edac_dev, unsigned long value);
extern void edac_mc_reset_delay_period(int value);
-extern void *edac_align_ptr(void *ptr, unsigned size);
+extern void *edac_align_ptr(void **p, unsigned size, int n_elems);
/*
* EDAC PCI functions
diff --git a/drivers/edac/edac_pci.c b/drivers/edac/edac_pci.c
index 63af1c5..f1ac866 100644
--- a/drivers/edac/edac_pci.c
+++ b/drivers/edac/edac_pci.c
@@ -42,13 +42,13 @@ struct edac_pci_ctl_info *edac_pci_alloc_ctl_info(unsigned int sz_pvt,
const char *edac_pci_name)
{
struct edac_pci_ctl_info *pci;
- void *pvt;
+ void *p = NULL, *pvt;
unsigned int size;
debugf1("%s()\n", __func__);
- pci = (struct edac_pci_ctl_info *)0;
- pvt = edac_align_ptr(&pci[1], sz_pvt);
+ pci = edac_align_ptr(&p, sizeof(*pci), 1);
+ pvt = edac_align_ptr(&p, 1, sz_pvt);
size = ((unsigned long)pvt) + sz_pvt;
/* Alloc the needed control struct memory */
--
1.7.8
--
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