From: Michal Nazarewicz <m.nazarewicz@xxxxxxxxxxx>
This commits adds vcm_phys_alloc() function with some
accompanying functions which allocates physical memory. This
should be used from withing alloc or phys callback of a VCM
driver if one does not want to provide its own allocator.
Signed-off-by: Michal Nazarewicz <m.nazarewicz@xxxxxxxxxxx>
Signed-off-by: Kyungmin Park <kyungmin.park@xxxxxxxxxxx>
---
Documentation/virtual-contiguous-memory.txt | 31 ++++
include/linux/vcm-drv.h | 88 ++++++++++
mm/Kconfig | 9 +
mm/vcm.c | 249 +++++++++++++++++++++++++++
4 files changed, 377 insertions(+), 0 deletions(-)
diff --git a/Documentation/virtual-contiguous-memory.txt b/Documentation/virtual-contiguous-memory.txt
index 9793a86..56924df 100644
--- a/Documentation/virtual-contiguous-memory.txt
+++ b/Documentation/virtual-contiguous-memory.txt
@@ -644,6 +644,37 @@ Both phys and alloc callbacks need to provide a free callbakc along
with the vc_phys structure, which will, as one may imagine, free
allocated space when user calls vcm_free().
+Unless VCM driver needs some special handling of physical memory, the
+vcm_phys_alloc() function can be used:
+
+ struct vcm_phys *__must_check
+ vcm_phys_alloc(resource_size_t size, unsigned flags,
+ const unsigned char *orders);
+
+The last argument of this function (orders) is an array of orders of
+page sizes that function should try to allocate. This array must be
+sorted from highest order to lowest and the last entry must be zero.
+
+For instance, an array { 8, 4, 0 } means that the function should try
+and allocate 1MiB, 64KiB and 4KiB pages (this is assuming PAGE_SIZE is
+4KiB which is true for all supported architectures). For example, if
+requested size is 2MiB and 68 KiB, the function will try to allocate
+two 1MiB pages, one 64KiB page and one 4KiB page. This may be useful
+when the mapping is written to the MMU since the largest possible
+pages will be used reducing the number of entries.
+
+The function allocates memory from DMA32 zone. If driver has some
+other requirements (that is require different GFP flags) it can use
+__vcm_phys_alloc() function which, besides arguments that
+vcm_phys_alloc() accepts, take GFP flags as the last argument:
+
+ struct vcm_phys *__must_check
+ __vcm_phys_alloc(resource_size_t size, unsigned flags,
+ const unsigned char *orders, gfp_t gfp);
+
+However, if those functions are used, VCM driver needs to select an
+VCM_PHYS Kconfig option or oterwise they won't be available.
+
All those operations may assume that size is a non-zero and divisible
by PAGE_SIZE.
diff --git a/include/linux/vcm-drv.h b/include/linux/vcm-drv.h
index d7ae660..536b051 100644
--- a/include/linux/vcm-drv.h
+++ b/include/linux/vcm-drv.h
@@ -114,4 +114,92 @@ struct vcm_phys {
*/
struct vcm *__must_check vcm_init(struct vcm *vcm);
+#ifdef CONFIG_VCM_PHYS
+
+/**
+ * __vcm_phys_alloc() - allocates physical discontiguous space
+ * @size: size of the block to allocate.
+ * @flags: additional allocation flags; XXX FIXME: document
+ * @orders: array of orders of pages supported by the MMU sorted from
+ * the largest to the smallest. The last element is always
+ * zero (which means 4K page).
+ * @gfp: the gfp flags for pages to allocate.
+ *
+ * This function tries to allocate a physical discontiguous space in
+ * such a way that it allocates the largest possible blocks from the
+ * sizes donated by the @orders array. So if @orders is { 8, 0 }
+ * (which means 1MiB and 4KiB pages are to be used) and requested
+ * @size is 2MiB and 12KiB the function will try to allocate two 1MiB
+ * pages and three 4KiB pages (in that order). If big page cannot be
+ * allocated the function will still try to allocate more smaller
+ * pages.
+ */
+struct vcm_phys *__must_check
+__vcm_phys_alloc(resource_size_t size, unsigned flags,
+ const unsigned char *orders, gfp_t gfp);
+
+/**
+ * vcm_phys_alloc() - allocates physical discontiguous space
+ * @size: size of the block to allocate.
+ * @flags: additional allocation flags; XXX FIXME: document
+ * @orders: array of orders of pages supported by the MMU sorted from
+ * the largest to the smallest. The last element is always
+ * zero (which means 4K page).
+ *
+ * This function tries to allocate a physical discontiguous space in
+ * such a way that it allocates the largest possible blocks from the
+ * sizes donated by the @orders array. So if @orders is { 8, 0 }
+ * (which means 1MiB and 4KiB pages are to be used) and requested
+ * @size is 2MiB and 12KiB the function will try to allocate two 1MiB
+ * pages and three 4KiB pages (in that order). If big page cannot be
+ * allocated the function will still try to allocate more smaller
+ * pages.
+ */
+static inline struct vcm_phys *__must_check
+vcm_phys_alloc(resource_size_t size, unsigned flags,
+ const unsigned char *orders) {
+ return __vcm_phys_alloc(size, flags, orders, GFP_DMA32);
+}
+
+/**
+ * vcm_phys_walk() - helper function for mapping physical pages
+ * @vaddr: virtual address to map/unmap physical space to/from
+ * @phys: physical space
+ * @orders: array of orders of pages supported by the MMU sorted from
+ * the largest to the smallest. The last element is always
+ * zero (which means 4K page).
+ * @callback: function called for each page.
+ * @recover: function called for each page when @callback returns
+ * negative number; if it also returns negative number
+ * function terminates; may be NULL.
+ * @priv: private data for the callbacks.
+ *
+ * This function walks through @phys trying to mach largest possible
+ * page size donated by @orders. For each such page @callback is
+ * called. If @callback returns negative number the function calls
+ * @recover for each page @callback was called successfully.
+ *
+ * So, for instance, if we have a physical memory which consist of
+ * 1Mib part and 8KiB part and @orders is { 8, 0 } (which means 1MiB
+ * and 4KiB pages are to be used), @callback will be called first with
+ * 1MiB page and then two times with 4KiB page. This is of course
+ * provided that @vaddr has correct alignment.
+ *
+ * The idea is for hardware MMU drivers to call this function and
+ * provide a callbacks for mapping/unmapping a single page. The
+ * function divides the region into pages that the MMU can handle.
+ *
+ * If @callback at one point returns a negative number this is the
+ * return value of the function; otherwise zero is returned.
+ */
+int vcm_phys_walk(dma_addr_t vaddr, const struct vcm_phys *phys,
+ const unsigned char *orders,
+ int (*callback)(dma_addr_t vaddr, dma_addr_t paddr,
+ unsigned order, void *priv),
+ int (*recovery)(dma_addr_t vaddr, dma_addr_t paddr,
+ unsigned order, void *priv),
+ void *priv);
+
+#endif
+
#endif
diff --git a/mm/Kconfig b/mm/Kconfig
index cfe1601..70fc7ed 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -386,6 +386,15 @@ config VCM
<Documentation/virtual-contiguous-memory.txt>. If unsure, say
"n".
+config VCM_PHYS
+ bool "VCM physical allocation wrappers"
+ depends on VCM && MODULES
+ help
+ This enables the vcm_phys family of functions provided for VCM
+ drivers. If a VCM driver is built that requires this option, it
+ will be automatically selected. You select it if you are going to
+ build external modules that will use this functionality.
+
#
# UP and nommu archs use km based percpu allocator
#
diff --git a/mm/vcm.c b/mm/vcm.c
index 1389ee6..a9c5161 100644
--- a/mm/vcm.c
+++ b/mm/vcm.c
@@ -302,3 +302,252 @@ struct vcm *__must_check vcm_init(struct vcm *vcm)
return vcm;
}
EXPORT_SYMBOL_GPL(vcm_init);
+
+
+/************************ Physical memory management ************************/
+
+#ifdef CONFIG_VCM_PHYS
+
+struct vcm_phys_list {
+ struct vcm_phys_list *next;
+ unsigned count;
+ struct vcm_phys_part parts[31];
+};
+
+static struct vcm_phys_list *__must_check
+vcm_phys_alloc_list_order(struct vcm_phys_list *last, resource_size_t *pages,
+ unsigned flags, unsigned order, unsigned *total,
+ gfp_t gfp)
+{
+ unsigned count;
+
+ count = *pages >> order;
+
+ do {
+ struct page *page = alloc_pages(gfp, order);
+
+ if (!page)
+ /*
+ * If allocation failed we may still
+ * try to continua allocating smaller
+ * pages.
+ */
+ break;
+
+ if (last->count == ARRAY_SIZE(last->parts)) {
+ struct vcm_phys_list *l;
+ l = kmalloc(sizeof *l, GFP_KERNEL);
+ if (!l)
+ return NULL;
+
+ l->next = NULL;
+ l->count = 0;
+ last->next = l;
+ last = l;
+ }
+
+ last->parts[last->count].start = page_to_phys(page);
+ last->parts[last->count].size = (1 << order);
+ last->parts[last->count].page = page;
+ ++last->count;
+ ++*total;
+ *pages -= 1 << order;
+ } while (--count);
+
+ return last;
+}
+
+static unsigned __must_check
+vcm_phys_alloc_list(struct vcm_phys_list *first,
+ resource_size_t size, unsigned flags,
+ const unsigned char *orders, gfp_t gfp)
+{
+ struct vcm_phys_list *last = first;
+ unsigned total_parts = 0;
+ resource_size_t pages;
+
+ /*
+ * We are trying to allocate as large pages as possible but
+ * not larger then pages that MMU driver that called us
+ * supports (ie. the ones provided by page_sizes). This makes
+ * it possible to map the region using fewest possible number
+ * of entries.
+ */
+ pages = size >> PAGE_SHIFT;
+ do {
+ while (!(pages >> *orders))
+ ++orders;
+
+ last = vcm_phys_alloc_list_order(last, &pages, flags, *orders,
+ &total_parts, gfp);
+ if (!last)
+ return 0;
+
+ } while (*orders++ && pages);
+
+ if (pages)
+ return 0;
+
+ return total_parts;
+}
+
+static void vcm_phys_free_parts(struct vcm_phys_part *parts, unsigned count)
+{
+ do {
+ __free_pages(parts->page, ffs(parts->size) - 1 - PAGE_SHIFT);
+ } while (++parts, --count);
+}
+
+static void vcm_phys_free(struct vcm_phys *phys)
+{
+ vcm_phys_free_parts(phys->parts, phys->count);
+ kfree(phys);
+}
+
+struct vcm_phys *__must_check
+__vcm_phys_alloc(resource_size_t size, unsigned flags,
+ const unsigned char *orders, gfp_t gfp)
+{
+ struct vcm_phys_list *lst, *n;
+ struct vcm_phys_part *out;
+ struct vcm_phys *phys;
+ unsigned count;
+
+ if (WARN_ON((size & (PAGE_SIZE - 1)) || !size || !orders))
+ return ERR_PTR(-EINVAL);
+
+ lst = kmalloc(sizeof *lst, GFP_KERNEL);
+ if (!lst)
+ return ERR_PTR(-ENOMEM);
+
+ lst->next = NULL;
+ lst->count = 0;
+
+ count = vcm_phys_alloc_list(lst, size, flags, orders, gfp);
+ if (!count)
+ goto error;
+
+ phys = kmalloc(sizeof *phys + count * sizeof *phys->parts, GFP_KERNEL);
+ if (!phys)
+ goto error;
+
+ phys->free = vcm_phys_free;
+ phys->count = count;
+ phys->size = size;
+
+ out = phys->parts;
+ do {
+ memcpy(out, lst->parts, lst->count * sizeof *out);
+ out += lst->count;
+
+ n = lst->next;
+ kfree(lst);
+ lst = n;
+ } while (lst);
+
+ return phys;
+
+error:
+ do {
+ vcm_phys_free_parts(lst->parts, lst->count);
+
+ n = lst->next;
+ kfree(lst);
+ lst = n;
+ } while (lst);
+
+ return ERR_PTR(-ENOMEM);
+}
+EXPORT_SYMBOL_GPL(__vcm_phys_alloc);
+
+static inline bool is_of_order(dma_addr_t size, unsigned order)
+{
+ return !(size & (((dma_addr_t)PAGE_SIZE << order) - 1));
+}
+
+static int
+__vcm_phys_walk_part(dma_addr_t vaddr, const struct vcm_phys_part *part,
+ const unsigned char *orders,
+ int (*callback)(dma_addr_t vaddr, dma_addr_t paddr,
+ unsigned order, void *priv), void *priv,
+ unsigned *limit)
+{
+ resource_size_t size = part->size;
+ dma_addr_t paddr = part->start;
+ resource_size_t ps;
+
+ while (!is_of_order(vaddr, *orders))
+ ++orders;
+ while (!is_of_order(paddr, *orders))
+ ++orders;
+
+ ps = PAGE_SIZE << *orders;
+ for (; *limit && size; --*limit) {
+ int ret;
+
+ while (ps > size)
+ ps = PAGE_SIZE << *++orders;
+
+ ret = callback(vaddr, paddr, *orders, priv);
+ if (ret < 0)
+ return ret;
+
+ ps = PAGE_SIZE << *orders;
+ vaddr += ps;
+ paddr += ps;
+ size -= ps;
+ }
+
+ return 0;
+}
+
+int vcm_phys_walk(dma_addr_t _vaddr, const struct vcm_phys *phys,
+ const unsigned char *orders,
+ int (*callback)(dma_addr_t vaddr, dma_addr_t paddr,
+ unsigned order, void *arg),
+ int (*recovery)(dma_addr_t vaddr, dma_addr_t paddr,
+ unsigned order, void *arg),
+ void *priv)
+{
+ unsigned limit = ~0;
+ int r = 0;
+
+ if (WARN_ON(!phys || ((_vaddr | phys->size) & (PAGE_SIZE - 1)) ||
+ !phys->size || !orders || !callback))
+ return -EINVAL;
+
+ for (;;) {
+ const struct vcm_phys_part *part = phys->parts;
+ unsigned count = phys->count;
+ dma_addr_t vaddr = _vaddr;
+ int ret = 0;
+
+ for (; count && limit; --count, ++part) {
+ ret = __vcm_phys_walk_part(vaddr, part, orders,
+ callback, priv, &limit);
+ if (ret)
+ break;
+
+ vaddr += part->size;
+ }
+
+ if (r)
+ /* We passed error recovery */
+ return r;
+
+ /*
+ * Either operation suceeded or we were not provided
+ * with a recovery callback -- return.
+ */
+ if (!ret || !recovery)
+ return ret;
+
+ /* Switch to recovery */
+ limit = ~0 - limit;
+ callback = recovery;
+ r = ret;
+ }
+}
+EXPORT_SYMBOL_GPL(vcm_phys_walk);
+
+#endif
--
1.6.2.5
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