forked from Minki/linux
exofs: avoid VLA in structures
On the quest to remove all VLAs from the kernel[1] this adjusts several cases where allocation is made after an array of structures that points back into the allocation. The allocations are changed to perform explicit calculations instead of using a Variable Length Array in a structure. Additionally, this lets Clang compile this code now, since Clang does not support VLAIS[2]. [1] https://lkml.kernel.org/r/CA+55aFzCG-zNmZwX4A2FQpadafLfEzK6CC=qPXydAacU1RqZWA@mail.gmail.com [2] https://lkml.kernel.org/r/CA+55aFy6h1c3_rP_bXFedsTXzwW+9Q9MfJaW7GUmMBrAp-fJ9A@mail.gmail.com [keescook@chromium.org: v2] Link: http://lkml.kernel.org/r/20180418163546.GA45794@beast Link: http://lkml.kernel.org/r/20180327203904.GA1151@beast Signed-off-by: Kees Cook <keescook@chromium.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Cc: Boaz Harrosh <ooo@electrozaur.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Kees Cook
Linus Torvalds
parent
86a2bb5ad8
commit
20fe935358
@ -146,68 +146,82 @@ int _ore_get_io_state(struct ore_layout *layout,
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struct ore_io_state **pios)
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{
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struct ore_io_state *ios;
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struct page **pages;
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struct osd_sg_entry *sgilist;
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size_t size_ios, size_extra, size_total;
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void *ios_extra;
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/*
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* The desired layout looks like this, with the extra_allocation
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* items pointed at from fields within ios or per_dev:
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struct __alloc_all_io_state {
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struct ore_io_state ios;
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struct ore_per_dev_state per_dev[numdevs];
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union {
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struct osd_sg_entry sglist[sgs_per_dev * numdevs];
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struct page *pages[num_par_pages];
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};
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} *_aios;
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} extra_allocation;
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} whole_allocation;
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if (likely(sizeof(*_aios) <= PAGE_SIZE)) {
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_aios = kzalloc(sizeof(*_aios), GFP_KERNEL);
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if (unlikely(!_aios)) {
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ORE_DBGMSG("Failed kzalloc bytes=%zd\n",
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sizeof(*_aios));
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*/
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/* This should never happen, so abort early if it ever does. */
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if (sgs_per_dev && num_par_pages) {
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ORE_DBGMSG("Tried to use both pages and sglist\n");
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*pios = NULL;
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return -EINVAL;
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}
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if (numdevs > (INT_MAX - sizeof(*ios)) /
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sizeof(struct ore_per_dev_state))
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return -ENOMEM;
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size_ios = sizeof(*ios) + sizeof(struct ore_per_dev_state) * numdevs;
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if (sgs_per_dev * numdevs > INT_MAX / sizeof(struct osd_sg_entry))
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return -ENOMEM;
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if (num_par_pages > INT_MAX / sizeof(struct page *))
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return -ENOMEM;
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size_extra = max(sizeof(struct osd_sg_entry) * (sgs_per_dev * numdevs),
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sizeof(struct page *) * num_par_pages);
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size_total = size_ios + size_extra;
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if (likely(size_total <= PAGE_SIZE)) {
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ios = kzalloc(size_total, GFP_KERNEL);
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if (unlikely(!ios)) {
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ORE_DBGMSG("Failed kzalloc bytes=%zd\n", size_total);
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*pios = NULL;
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return -ENOMEM;
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}
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pages = num_par_pages ? _aios->pages : NULL;
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sgilist = sgs_per_dev ? _aios->sglist : NULL;
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ios = &_aios->ios;
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ios_extra = (char *)ios + size_ios;
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} else {
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struct __alloc_small_io_state {
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struct ore_io_state ios;
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struct ore_per_dev_state per_dev[numdevs];
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} *_aio_small;
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union __extra_part {
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struct osd_sg_entry sglist[sgs_per_dev * numdevs];
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struct page *pages[num_par_pages];
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} *extra_part;
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_aio_small = kzalloc(sizeof(*_aio_small), GFP_KERNEL);
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if (unlikely(!_aio_small)) {
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ios = kzalloc(size_ios, GFP_KERNEL);
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if (unlikely(!ios)) {
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ORE_DBGMSG("Failed alloc first part bytes=%zd\n",
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sizeof(*_aio_small));
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size_ios);
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*pios = NULL;
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return -ENOMEM;
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}
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extra_part = kzalloc(sizeof(*extra_part), GFP_KERNEL);
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if (unlikely(!extra_part)) {
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ios_extra = kzalloc(size_extra, GFP_KERNEL);
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if (unlikely(!ios_extra)) {
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ORE_DBGMSG("Failed alloc second part bytes=%zd\n",
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sizeof(*extra_part));
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kfree(_aio_small);
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size_extra);
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kfree(ios);
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*pios = NULL;
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return -ENOMEM;
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}
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pages = num_par_pages ? extra_part->pages : NULL;
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sgilist = sgs_per_dev ? extra_part->sglist : NULL;
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/* In this case the per_dev[0].sgilist holds the pointer to
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* be freed
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*/
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ios = &_aio_small->ios;
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ios->extra_part_alloc = true;
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}
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if (pages) {
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ios->parity_pages = pages;
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if (num_par_pages) {
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ios->parity_pages = ios_extra;
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ios->max_par_pages = num_par_pages;
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}
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if (sgilist) {
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if (sgs_per_dev) {
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struct osd_sg_entry *sgilist = ios_extra;
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unsigned d;
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for (d = 0; d < numdevs; ++d) {
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@ -71,6 +71,11 @@ static int _sp2d_alloc(unsigned pages_in_unit, unsigned group_width,
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{
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struct __stripe_pages_2d *sp2d;
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unsigned data_devs = group_width - parity;
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/*
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* Desired allocation layout is, though when larger than PAGE_SIZE,
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* each struct __alloc_1p_arrays is separately allocated:
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struct _alloc_all_bytes {
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struct __alloc_stripe_pages_2d {
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struct __stripe_pages_2d sp2d;
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@ -82,55 +87,85 @@ static int _sp2d_alloc(unsigned pages_in_unit, unsigned group_width,
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char page_is_read[data_devs];
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} __a1pa[pages_in_unit];
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} *_aab;
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struct __alloc_1p_arrays *__a1pa;
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struct __alloc_1p_arrays *__a1pa_end;
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const unsigned sizeof__a1pa = sizeof(_aab->__a1pa[0]);
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*/
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char *__a1pa;
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char *__a1pa_end;
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const size_t sizeof_stripe_pages_2d =
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sizeof(struct __stripe_pages_2d) +
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sizeof(struct __1_page_stripe) * pages_in_unit;
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const size_t sizeof__a1pa =
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ALIGN(sizeof(struct page *) * (2 * group_width) + data_devs,
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sizeof(void *));
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const size_t sizeof__a1pa_arrays = sizeof__a1pa * pages_in_unit;
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const size_t alloc_total = sizeof_stripe_pages_2d +
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sizeof__a1pa_arrays;
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unsigned num_a1pa, alloc_size, i;
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/* FIXME: check these numbers in ore_verify_layout */
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BUG_ON(sizeof(_aab->__asp2d) > PAGE_SIZE);
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BUG_ON(sizeof_stripe_pages_2d > PAGE_SIZE);
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BUG_ON(sizeof__a1pa > PAGE_SIZE);
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if (sizeof(*_aab) > PAGE_SIZE) {
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num_a1pa = (PAGE_SIZE - sizeof(_aab->__asp2d)) / sizeof__a1pa;
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alloc_size = sizeof(_aab->__asp2d) + sizeof__a1pa * num_a1pa;
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/*
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* If alloc_total would be larger than PAGE_SIZE, only allocate
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* as many a1pa items as would fill the rest of the page, instead
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* of the full pages_in_unit count.
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*/
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if (alloc_total > PAGE_SIZE) {
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num_a1pa = (PAGE_SIZE - sizeof_stripe_pages_2d) / sizeof__a1pa;
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alloc_size = sizeof_stripe_pages_2d + sizeof__a1pa * num_a1pa;
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} else {
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num_a1pa = pages_in_unit;
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alloc_size = sizeof(*_aab);
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alloc_size = alloc_total;
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}
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_aab = kzalloc(alloc_size, GFP_KERNEL);
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if (unlikely(!_aab)) {
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*psp2d = sp2d = kzalloc(alloc_size, GFP_KERNEL);
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if (unlikely(!sp2d)) {
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ORE_DBGMSG("!! Failed to alloc sp2d size=%d\n", alloc_size);
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return -ENOMEM;
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}
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/* From here Just call _sp2d_free */
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sp2d = &_aab->__asp2d.sp2d;
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*psp2d = sp2d; /* From here Just call _sp2d_free */
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__a1pa = _aab->__a1pa;
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__a1pa_end = __a1pa + num_a1pa;
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/* Find start of a1pa area. */
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__a1pa = (char *)sp2d + sizeof_stripe_pages_2d;
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/* Find end of the _allocated_ a1pa area. */
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__a1pa_end = __a1pa + alloc_size;
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/* Allocate additionally needed a1pa items in PAGE_SIZE chunks. */
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for (i = 0; i < pages_in_unit; ++i) {
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struct __1_page_stripe *stripe = &sp2d->_1p_stripes[i];
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if (unlikely(__a1pa >= __a1pa_end)) {
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num_a1pa = min_t(unsigned, PAGE_SIZE / sizeof__a1pa,
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pages_in_unit - i);
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alloc_size = sizeof__a1pa * num_a1pa;
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__a1pa = kcalloc(num_a1pa, sizeof__a1pa, GFP_KERNEL);
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__a1pa = kzalloc(alloc_size, GFP_KERNEL);
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if (unlikely(!__a1pa)) {
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ORE_DBGMSG("!! Failed to _alloc_1p_arrays=%d\n",
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num_a1pa);
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return -ENOMEM;
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}
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__a1pa_end = __a1pa + num_a1pa;
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__a1pa_end = __a1pa + alloc_size;
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/* First *pages is marked for kfree of the buffer */
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sp2d->_1p_stripes[i].alloc = true;
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stripe->alloc = true;
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}
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sp2d->_1p_stripes[i].pages = __a1pa->pages;
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sp2d->_1p_stripes[i].scribble = __a1pa->scribble ;
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sp2d->_1p_stripes[i].page_is_read = __a1pa->page_is_read;
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++__a1pa;
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/*
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* Attach all _lp_stripes pointers to the allocation for
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* it which was either part of the original PAGE_SIZE
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* allocation or the subsequent allocation in this loop.
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*/
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stripe->pages = (void *)__a1pa;
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stripe->scribble = stripe->pages + group_width;
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stripe->page_is_read = (char *)stripe->scribble + group_width;
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__a1pa += sizeof__a1pa;
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}
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sp2d->parity = parity;
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@ -549,27 +549,26 @@ static int exofs_devs_2_odi(struct exofs_dt_device_info *dt_dev,
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static int __alloc_dev_table(struct exofs_sb_info *sbi, unsigned numdevs,
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struct exofs_dev **peds)
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{
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struct __alloc_ore_devs_and_exofs_devs {
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/* Twice bigger table: See exofs_init_comps() and comment at
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* exofs_read_lookup_dev_table()
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*/
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struct ore_dev *oreds[numdevs * 2 - 1];
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struct exofs_dev eds[numdevs];
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} *aoded;
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/* Twice bigger table: See exofs_init_comps() and comment at
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* exofs_read_lookup_dev_table()
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*/
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const size_t numores = numdevs * 2 - 1;
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struct exofs_dev *eds;
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unsigned i;
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aoded = kzalloc(sizeof(*aoded), GFP_KERNEL);
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if (unlikely(!aoded)) {
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sbi->oc.ods = kzalloc(numores * sizeof(struct ore_dev *) +
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numdevs * sizeof(struct exofs_dev), GFP_KERNEL);
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if (unlikely(!sbi->oc.ods)) {
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EXOFS_ERR("ERROR: failed allocating Device array[%d]\n",
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numdevs);
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return -ENOMEM;
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}
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sbi->oc.ods = aoded->oreds;
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*peds = eds = aoded->eds;
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/* Start of allocated struct exofs_dev entries */
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*peds = eds = (void *)sbi->oc.ods[numores];
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/* Initialize pointers into struct exofs_dev */
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for (i = 0; i < numdevs; ++i)
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aoded->oreds[i] = &eds[i].ored;
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sbi->oc.ods[i] = &eds[i].ored;
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return 0;
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}
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