bpf: Use bytes instead of pages for bpf_jit_[charge|uncharge]_modmem

This enables sub-page memory charge and allocation.

Signed-off-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220204185742.271030-3-song@kernel.org

diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index 6eb0b180d33b42421eedba5e62a8ddd61967d806..366f88afd56b4c7a86d378dbf2e33e664e5eb812 100644 (file)
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -846,8 +846,8 @@ void bpf_image_ksym_add(void *data, struct bpf_ksym *ksym);
 void bpf_image_ksym_del(struct bpf_ksym *ksym);
 void bpf_ksym_add(struct bpf_ksym *ksym);
 void bpf_ksym_del(struct bpf_ksym *ksym);
-int bpf_jit_charge_modmem(u32 pages);
-void bpf_jit_uncharge_modmem(u32 pages);
+int bpf_jit_charge_modmem(u32 size);
+void bpf_jit_uncharge_modmem(u32 size);
 bool bpf_prog_has_trampoline(const struct bpf_prog *prog);
 #else
 static inline int bpf_trampoline_link_prog(struct bpf_prog *prog,

diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
index 04a8d5bea552d9e6e3985967d0ea563cf0306f1f..6ca0550c4b24f0d8734799d51afb1cbdb8736be4 100644 (file)
--- a/kernel/bpf/core.c
+++ b/kernel/bpf/core.c
@@ -833,12 +833,11 @@ static int __init bpf_jit_charge_init(void)
 }
 pure_initcall(bpf_jit_charge_init);
 
-int bpf_jit_charge_modmem(u32 pages)
+int bpf_jit_charge_modmem(u32 size)
 {
-       if (atomic_long_add_return(pages, &bpf_jit_current) >
-           (bpf_jit_limit >> PAGE_SHIFT)) {
+       if (atomic_long_add_return(size, &bpf_jit_current) > bpf_jit_limit) {
                if (!bpf_capable()) {
-                       atomic_long_sub(pages, &bpf_jit_current);
+                       atomic_long_sub(size, &bpf_jit_current);
                        return -EPERM;
                }
        }
@@ -846,9 +845,9 @@ int bpf_jit_charge_modmem(u32 pages)
        return 0;
 }
 
-void bpf_jit_uncharge_modmem(u32 pages)
+void bpf_jit_uncharge_modmem(u32 size)
 {
-       atomic_long_sub(pages, &bpf_jit_current);
+       atomic_long_sub(size, &bpf_jit_current);
 }
 
 void *__weak bpf_jit_alloc_exec(unsigned long size)
@@ -879,11 +878,11 @@ bpf_jit_binary_alloc(unsigned int proglen, u8 **image_ptr,
        size = round_up(proglen + sizeof(*hdr) + 128, PAGE_SIZE);
        pages = size / PAGE_SIZE;
 
-       if (bpf_jit_charge_modmem(pages))
+       if (bpf_jit_charge_modmem(size))
                return NULL;
        hdr = bpf_jit_alloc_exec(size);
        if (!hdr) {
-               bpf_jit_uncharge_modmem(pages);
+               bpf_jit_uncharge_modmem(size);
                return NULL;
        }
 
@@ -906,7 +905,7 @@ void bpf_jit_binary_free(struct bpf_binary_header *hdr)
        u32 pages = hdr->pages;
 
        bpf_jit_free_exec(hdr);
-       bpf_jit_uncharge_modmem(pages);
+       bpf_jit_uncharge_modmem(pages << PAGE_SHIFT);
 }
 
 /* This symbol is only overridden by archs that have different

diff --git a/kernel/bpf/trampoline.c b/kernel/bpf/trampoline.c
index 4b6974a195c138a3a69611408473c1c6d0d8f99f..e76a488c09c3eb51eaacd501caefa537f5a0d437 100644 (file)
--- a/kernel/bpf/trampoline.c
+++ b/kernel/bpf/trampoline.c
@@ -213,7 +213,7 @@ static void __bpf_tramp_image_put_deferred(struct work_struct *work)
        im = container_of(work, struct bpf_tramp_image, work);
        bpf_image_ksym_del(&im->ksym);
        bpf_jit_free_exec(im->image);
-       bpf_jit_uncharge_modmem(1);
+       bpf_jit_uncharge_modmem(PAGE_SIZE);
        percpu_ref_exit(&im->pcref);
        kfree_rcu(im, rcu);
 }
@@ -310,7 +310,7 @@ static struct bpf_tramp_image *bpf_tramp_image_alloc(u64 key, u32 idx)
        if (!im)
                goto out;
 
-       err = bpf_jit_charge_modmem(1);
+       err = bpf_jit_charge_modmem(PAGE_SIZE);
        if (err)
                goto out_free_im;
 
@@ -332,7 +332,7 @@ static struct bpf_tramp_image *bpf_tramp_image_alloc(u64 key, u32 idx)
 out_free_image:
        bpf_jit_free_exec(im->image);
 out_uncharge:
-       bpf_jit_uncharge_modmem(1);
+       bpf_jit_uncharge_modmem(PAGE_SIZE);
 out_free_im:
        kfree(im);
 out: