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    SubjectRe: [EDAC ABI v13 24/25] edac: change the mem allocation scheme to make Documentation/kobject.txt happy
    Hi Joe,

    Em 17-04-2012 18:17, Joe Perches escreveu:
    > On Mon, 2012-04-16 at 17:38 -0300, Mauro Carvalho Chehab wrote:
    >> Kernel kobjects have rigid rules: each container object should be
    >> dynamically allocated, and can't be allocated into a single kmalloc.
    >>
    >> EDAC never obeyed this rule: it has a single malloc function that
    >> allocates all needed data into a single kzalloc.
    >>
    >> As this is not accepted anymore, change the allocation schema of the
    >> EDAC *_info structs to enforce this Kernel standard.
    > []
    >> diff --git a/drivers/edac/amd64_edac.c b/drivers/edac/amd64_edac.c
    > []
    >> @@ -2228,9 +2228,9 @@ static int init_csrows(struct mem_ctl_info *mci)
    >> edac_mode = EDAC_NONE;
    >>
    >> for (j = 0; j < pvt->channel_count; j++) {
    >> - csrow->channels[j].dimm->mtype = mtype;
    >> - csrow->channels[j].dimm->edac_mode = edac_mode;
    >> - csrow->channels[j].dimm->nr_pages = nr_pages;
    >> + csrow->channels[j]->dimm->mtype = mtype;
    >> + csrow->channels[j]->dimm->edac_mode = edac_mode;
    >> + csrow->channels[j]->dimm->nr_pages = nr_pages;
    >
    > It might be better to use an automatic for
    > typeof foo dimm = csrow->channels[j]->dimm;
    > dimm->mtype = mtype;
    > etc...
    > []
    >> @@ -293,39 +286,56 @@ struct mem_ctl_info *edac_mc_alloc(unsigned edac_index,
    >> mci->mem_is_per_rank = per_rank;
    >>
    >> /*
    >> - * Fills the csrow struct
    >> + * Alocate and fill the csrow/channels structs
    >> */
    >> + mci->csrows = kzalloc(sizeof(*mci->csrows) * tot_csrows, GFP_KERNEL);
    >
    > kcalloc
    >
    > []
    >> + csr->channels = kzalloc(sizeof(*csr->channels) * tot_cschannels,
    >> + GFP_KERNEL);
    >
    > here too
    >
    >> @@ -391,7 +401,31 @@ struct mem_ctl_info *edac_mc_alloc(unsigned edac_index,
    >>
    >> trace_hw_event_init("edac", (unsigned)edac_index);
    >>
    >> + debugf1("EDAC MCI allocated\n");
    >> return mci;

    Agreed with all above. Fixed.

    >> +
    >> +error:
    >> + debugf1("Failed to allocate one or more EDAC MCI structs\n");
    >
    > Generally, it's not necessary to have specific "OOM" messages
    > as allocations without GFP_NOWARN do dump_stack()s

    There is one error condition on the error path that might potentially happen
    that it is not related directly to the kalloc stuff: if, there GET_POS() tries
    to access something out of the allocated range, it bails out. I added this
    debug printk due to that, while testing the allocation changes. The check could
    potentially be using a BUG_ON() call, but, as failing here, the edac drivers
    will not load, I opted to not use BUG_ON, and, instead use the standard error
    path for it.

    That's said, it seems better to remove this debugf1 from this place, and add
    some printk(KERN_ERR, ...) at this specific condition.
    >
    >
    > --
    > To unsubscribe from this list: send the line "unsubscribe linux-edac" in
    > the body of a message to majordomo@vger.kernel.org
    > More majordomo info at http://vger.kernel.org/majordomo-info.html

    I'm folding the enclosed patch on this one, in order to address the comments
    on your review.


    Thanks!
    Mauro

    -

    diff --git a/drivers/edac/amd64_edac.c b/drivers/edac/amd64_edac.c
    index 16510a3..08af66c 100644
    --- a/drivers/edac/amd64_edac.c
    +++ b/drivers/edac/amd64_edac.c
    @@ -2180,6 +2180,7 @@ static u32 amd64_csrow_nr_pages(struct amd64_pvt *pvt, u8 dct, int csrow_nr)
    static int init_csrows(struct mem_ctl_info *mci)
    {
    struct csrow_info *csrow;
    + struct dimm_info *dimm;
    struct amd64_pvt *pvt = mci->pvt_info;
    u64 base, mask;
    u32 val;
    @@ -2228,9 +2229,10 @@ static int init_csrows(struct mem_ctl_info *mci)
    edac_mode = EDAC_NONE;

    for (j = 0; j < pvt->channel_count; j++) {
    - csrow->channels[j]->dimm->mtype = mtype;
    - csrow->channels[j]->dimm->edac_mode = edac_mode;
    - csrow->channels[j]->dimm->nr_pages = nr_pages;
    + dimm = csrow->channels[j]->dimm;
    + dimm->mtype = mtype;
    + dimm->edac_mode = edac_mode;
    + dimm->nr_pages = nr_pages;
    }
    }

    diff --git a/drivers/edac/edac_mc.c b/drivers/edac/edac_mc.c
    index fe57684..16f2d3b 100644
    --- a/drivers/edac/edac_mc.c
    +++ b/drivers/edac/edac_mc.c
    @@ -296,7 +296,7 @@ struct mem_ctl_info *edac_mc_alloc(unsigned edac_index,
    /*
    * Alocate and fill the csrow/channels structs
    */
    - mci->csrows = kzalloc(sizeof(*mci->csrows) * tot_csrows, GFP_KERNEL);
    + mci->csrows = kcalloc(sizeof(*mci->csrows), tot_csrows, GFP_KERNEL);
    if (!mci->csrows)
    goto error;
    for (row = 0; row < tot_csrows; row++) {
    @@ -307,7 +307,7 @@ struct mem_ctl_info *edac_mc_alloc(unsigned edac_index,
    csr->csrow_idx = row;
    csr->mci = mci;
    csr->nr_channels = tot_cschannels;
    - csr->channels = kzalloc(sizeof(*csr->channels) * tot_cschannels,
    + csr->channels = kcalloc(sizeof(*csr->channels), tot_cschannels,
    GFP_KERNEL);

    for (chn = 0; chn < tot_cschannels; chn++) {
    @@ -323,7 +323,7 @@ struct mem_ctl_info *edac_mc_alloc(unsigned edac_index,
    /*
    * Allocate and fill the dimm structs
    */
    - mci->dimms = kzalloc(sizeof(*mci->dimms) * tot_dimms, GFP_KERNEL);
    + mci->dimms = kcalloc(sizeof(*mci->dimms), tot_dimms, GFP_KERNEL);
    if (!mci->dimms)
    goto error;

    @@ -335,8 +335,10 @@ struct mem_ctl_info *edac_mc_alloc(unsigned edac_index,
    for (i = 0; i < tot_dimms; i++) {
    chan = mci->csrows[row]->channels[chn];
    off = GET_OFFSET(lay, n_layers, pos[0], pos[1], pos[2]);
    - if (off < 0 || off >= tot_dimms)
    + if (off < 0 || off >= tot_dimms) {
    + edac_mc_printk(mci, KERN_ERR, "EDAC core bug: GET_OFFSET is trying to do an illegal data access\n");
    goto error;
    + }

    dimm = kzalloc(sizeof(**mci->dimms), GFP_KERNEL);
    mci->dimms[off] = dimm;
    @@ -409,11 +411,9 @@ struct mem_ctl_info *edac_mc_alloc(unsigned edac_index,

    trace_hw_event_init("edac", (unsigned)edac_index);

    - debugf1("EDAC MCI allocated\n");
    return mci;

    error:
    - debugf1("Failed to allocate one or more EDAC MCI structs\n");
    if (mci->dimms) {
    for (i = 0; i < tot_dimms; i++)
    kfree(mci->dimms[i]);

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