EDAC/mc: Use kzalloc_flex()

Convert struct mem_ctl_info to use flex array and use the new flex array
helpers to enable runtime bounds checking, including annotating the array
length member with __counted_by() for extra runtime analysis when requested.

Move memcpy() after the counter assignment so that it is initialized before
the first reference to the flex array, as the new attribute requires.

  [ bp: Heavily massage commit message. ]

Signed-off-by: Rosen Penev <rosenp@gmail.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Yazen Ghannam <yazen.ghannam@amd.com>
Reviewed-by: Qiuxu Zhuo <qiuxu.zhuo@intel.com>
Link: https://patch.msgid.link/20260327024828.7377-1-rosenp@gmail.com

diff --git a/drivers/edac/edac_mc.c b/drivers/edac/edac_mc.c
index 29e9828422bb079a0d21abd7aff9cf8f7ad9feb4..07d3f73bcd237b45ed75bb4d89fc87976d8cffdc 100644 (file)
--- a/drivers/edac/edac_mc.c
+++ b/drivers/edac/edac_mc.c
@@ -203,7 +203,6 @@ static void mci_release(struct device *dev)
                kfree(mci->csrows);
        }
        kfree(mci->pvt_info);
-       kfree(mci->layers);
        kfree(mci);
 }
 
@@ -361,13 +360,12 @@ struct mem_ctl_info *edac_mc_alloc(unsigned int mc_num,
                        per_rank = true;
        }
 
-       mci = kzalloc_obj(struct mem_ctl_info);
+       mci = kzalloc_flex(*mci, layers, n_layers);
        if (!mci)
                return NULL;
 
-       mci->layers = kzalloc_objs(struct edac_mc_layer, n_layers);
-       if (!mci->layers)
-               goto error;
+       mci->n_layers = n_layers;
+       memcpy(mci->layers, layers, sizeof(*layer) * n_layers);
 
        mci->pvt_info = kzalloc(sz_pvt, GFP_KERNEL);
        if (!mci->pvt_info)
@@ -379,8 +377,6 @@ struct mem_ctl_info *edac_mc_alloc(unsigned int mc_num,
        /* setup index and various internal pointers */
        mci->mc_idx = mc_num;
        mci->tot_dimms = tot_dimms;
-       mci->n_layers = n_layers;
-       memcpy(mci->layers, layers, sizeof(*layer) * n_layers);
        mci->nr_csrows = tot_csrows;
        mci->num_cschannel = tot_channels;
        mci->csbased = per_rank;

diff --git a/include/linux/edac.h b/include/linux/edac.h
index fa32f2aca22fdf5143420e1851eb5821ecc688b7..deba46b3ee25d9ef226dde53c21635b41f1da972 100644 (file)
--- a/include/linux/edac.h
+++ b/include/linux/edac.h
@@ -541,17 +541,6 @@ struct mem_ctl_info {
        struct csrow_info **csrows;
        unsigned int nr_csrows, num_cschannel;
 
-       /*
-        * Memory Controller hierarchy
-        *
-        * There are basically two types of memory controller: the ones that
-        * sees memory sticks ("dimms"), and the ones that sees memory ranks.
-        * All old memory controllers enumerate memories per rank, but most
-        * of the recent drivers enumerate memories per DIMM, instead.
-        * When the memory controller is per rank, csbased is true.
-        */
-       unsigned int n_layers;
-       struct edac_mc_layer *layers;
        bool csbased;
 
        /*
@@ -609,6 +598,18 @@ struct mem_ctl_info {
        u8 fake_inject_layer[EDAC_MAX_LAYERS];
        bool fake_inject_ue;
        u16 fake_inject_count;
+
+       /*
+        * Memory Controller hierarchy
+        *
+        * There are basically two types of memory controller: the ones that
+        * sees memory sticks ("dimms"), and the ones that sees memory ranks.
+        * All old memory controllers enumerate memories per rank, but most
+        * of the recent drivers enumerate memories per DIMM, instead.
+        * When the memory controller is per rank, csbased is true.
+        */
+       unsigned int n_layers;
+       struct edac_mc_layer layers[] __counted_by(n_layers);
 };
 
 #define mci_for_each_dimm(mci, dimm)                           \