// SPDX-License-Identifier: GPL-2.0/* Copyright (c) 2017 - 2018 Covalent IO, Inc. http://covalent.io */ #include <linux/skmsg.h>#include <linux/skbuff.h>#include <linux/scatterlist.h> #include <net/sock.h>#include <net/tcp.h>#include <net/tls.h>#include <trace/events/sock.h> static bool sk_msg_try_coalesce_ok(struct sk_msg *msg, int elem_first_coalesce){ if (msg->sg.end > msg->sg.start && elem_first_coalesce < msg->sg.end) return true; if (msg->sg.end < msg->sg.start && (elem_first_coalesce > msg->sg.start || elem_first_coalesce < msg->sg.end)) return true; return false;} int sk_msg_alloc(struct sock *sk, struct sk_msg *msg, int len, int elem_first_coalesce){ struct page_frag *pfrag = sk_page_frag(sk); u32 osize = msg->sg.size; int ret = 0; len -= msg->sg.size; while (len > 0) { struct scatterlist *sge; u32 orig_offset; int use, i; if (!sk_page_frag_refill(sk, pfrag)) { ret = -ENOMEM; goto msg_trim; } orig_offset = pfrag->offset; use = min_t(int, len, pfrag->size - orig_offset); if (!sk_wmem_schedule(sk, use)) { ret = -ENOMEM; goto msg_trim; } i = msg->sg.end; sk_msg_iter_var_prev(i); sge = &msg->sg.data[i]; if (sk_msg_try_coalesce_ok(msg, elem_first_coalesce) && sg_page(sge) == pfrag->page && sge->offset + sge->length == orig_offset) { sge->length += use; } else { if (sk_msg_full(msg)) { ret = -ENOSPC; break; } sge = &msg->sg.data[msg->sg.end]; sg_unmark_end(sge); sg_set_page(sge, pfrag->page, use, orig_offset); get_page(pfrag->page); sk_msg_iter_next(msg, end); } sk_mem_charge(sk, use); msg->sg.size += use; pfrag->offset += use; len -= use; } return ret; msg_trim: sk_msg_trim(sk, msg, osize); return ret;}EXPORT_SYMBOL_GPL(sk_msg_alloc); int sk_msg_clone(struct sock *sk, struct sk_msg *dst, struct sk_msg *src, u32 off, u32 len){ int i = src->sg.start; struct scatterlist *sge = sk_msg_elem(src, i); struct scatterlist *sgd = NULL; u32 sge_len, sge_off; while (off) { if (sge->length > off) break; off -= sge->length; sk_msg_iter_var_next(i); if (i == src->sg.end && off) return -ENOSPC; sge = sk_msg_elem(src, i); } while (len) { sge_len = sge->length - off; if (sge_len > len) sge_len = len; if (dst->sg.end) sgd = sk_msg_elem(dst, dst->sg.end - 1); if (sgd && (sg_page(sge) == sg_page(sgd)) && (sg_virt(sge) + off == sg_virt(sgd) + sgd->length)) { sgd->length += sge_len; dst->sg.size += sge_len; } else if (!sk_msg_full(dst)) { sge_off = sge->offset + off; sk_msg_page_add(dst, sg_page(sge), sge_len, sge_off); } else { return -ENOSPC; } off = 0; len -= sge_len; sk_mem_charge(sk, sge_len); sk_msg_iter_var_next(i); if (i == src->sg.end && len) return -ENOSPC; sge = sk_msg_elem(src, i); } return 0;}EXPORT_SYMBOL_GPL(sk_msg_clone); void sk_msg_return_zero(struct sock *sk, struct sk_msg *msg, int bytes){ int i = msg->sg.start; do { struct scatterlist *sge = sk_msg_elem(msg, i); if (bytes < sge->length) { sge->length -= bytes; sge->offset += bytes; sk_mem_uncharge(sk, bytes); break; } sk_mem_uncharge(sk, sge->length); bytes -= sge->length; sge->length = 0; sge->offset = 0; sk_msg_iter_var_next(i); } while (bytes && i != msg->sg.end); msg->sg.start = i;}EXPORT_SYMBOL_GPL(sk_msg_return_zero); void sk_msg_return(struct sock *sk, struct sk_msg *msg, int bytes){ int i = msg->sg.start; do { struct scatterlist *sge = &msg->sg.data[i]; int uncharge = (bytes < sge->length) ? bytes : sge->length; sk_mem_uncharge(sk, uncharge); bytes -= uncharge; sk_msg_iter_var_next(i); } while (i != msg->sg.end);}EXPORT_SYMBOL_GPL(sk_msg_return); static int sk_msg_free_elem(struct sock *sk, struct sk_msg *msg, u32 i, bool charge){ struct scatterlist *sge = sk_msg_elem(msg, i); u32 len = sge->length; /* When the skb owns the memory we free it from consume_skb path. */ if (!msg->skb) { if (charge) sk_mem_uncharge(sk, len); put_page(sg_page(sge)); } memset(sge, 0, sizeof(*sge)); return len;} static int __sk_msg_free(struct sock *sk, struct sk_msg *msg, u32 i, bool charge){ struct scatterlist *sge = sk_msg_elem(msg, i); int freed = 0; while (msg->sg.size) { msg->sg.size -= sge->length; freed += sk_msg_free_elem(sk, msg, i, charge); sk_msg_iter_var_next(i); sk_msg_check_to_free(msg, i, msg->sg.size); sge = sk_msg_elem(msg, i); } consume_skb(msg->skb); sk_msg_init(msg); return freed;} int sk_msg_free_nocharge(struct sock *sk, struct sk_msg *msg){ return __sk_msg_free(sk, msg, msg->sg.start, false);}EXPORT_SYMBOL_GPL(sk_msg_free_nocharge); int sk_msg_free(struct sock *sk, struct sk_msg *msg){ return __sk_msg_free(sk, msg, msg->sg.start, true);}EXPORT_SYMBOL_GPL(sk_msg_free); static void __sk_msg_free_partial(struct sock *sk, struct sk_msg *msg, u32 bytes, bool charge){ struct scatterlist *sge; u32 i = msg->sg.start; while (bytes) { sge = sk_msg_elem(msg, i); if (!sge->length) break; if (bytes < sge->length) { if (charge) sk_mem_uncharge(sk, bytes); sge->length -= bytes; sge->offset += bytes; msg->sg.size -= bytes; break; } msg->sg.size -= sge->length; bytes -= sge->length; sk_msg_free_elem(sk, msg, i, charge); sk_msg_iter_var_next(i); sk_msg_check_to_free(msg, i, bytes); } msg->sg.start = i;} void sk_msg_free_partial(struct sock *sk, struct sk_msg *msg, u32 bytes){ __sk_msg_free_partial(sk, msg, bytes, true);}EXPORT_SYMBOL_GPL(sk_msg_free_partial); void sk_msg_free_partial_nocharge(struct sock *sk, struct sk_msg *msg, u32 bytes){ __sk_msg_free_partial(sk, msg, bytes, false);} void sk_msg_trim(struct sock *sk, struct sk_msg *msg, int len){ int trim = msg->sg.size - len; u32 i = msg->sg.end; if (trim <= 0) { WARN_ON(trim < 0); return; } sk_msg_iter_var_prev(i); msg->sg.size = len; while (msg->sg.data[i].length && trim >= msg->sg.data[i].length) { trim -= msg->sg.data[i].length; sk_msg_free_elem(sk, msg, i, true); sk_msg_iter_var_prev(i); if (!trim) goto out; } msg->sg.data[i].length -= trim; sk_mem_uncharge(sk, trim); /* Adjust copybreak if it falls into the trimmed part of last buf */ if (msg->sg.curr == i && msg->sg.copybreak > msg->sg.data[i].length) msg->sg.copybreak = msg->sg.data[i].length;out: sk_msg_iter_var_next(i); msg->sg.end = i; /* If we trim data a full sg elem before curr pointer update * copybreak and current so that any future copy operations * start at new copy location. * However trimmed data that has not yet been used in a copy op * does not require an update. */ if (!msg->sg.size) { msg->sg.curr = msg->sg.start; msg->sg.copybreak = 0; } else if (sk_msg_iter_dist(msg->sg.start, msg->sg.curr) >= sk_msg_iter_dist(msg->sg.start, msg->sg.end)) { sk_msg_iter_var_prev(i); msg->sg.curr = i; msg->sg.copybreak = msg->sg.data[i].length; }}EXPORT_SYMBOL_GPL(sk_msg_trim); int sk_msg_zerocopy_from_iter(struct sock *sk, struct iov_iter *from, struct sk_msg *msg, u32 bytes){ int i, maxpages, ret = 0, num_elems = sk_msg_elem_used(msg); const int to_max_pages = MAX_MSG_FRAGS; struct page *pages[MAX_MSG_FRAGS]; ssize_t orig, copied, use, offset; orig = msg->sg.size; while (bytes > 0) { i = 0; maxpages = to_max_pages - num_elems; if (maxpages == 0) { ret = -EFAULT; goto out; } copied = iov_iter_get_pages2(from, pages, bytes, maxpages, &offset); if (copied <= 0) { ret = -EFAULT; goto out; } bytes -= copied; msg->sg.size += copied; while (copied) { use = min_t(int, copied, PAGE_SIZE - offset); sg_set_page(&msg->sg.data[msg->sg.end], pages[i], use, offset); sg_unmark_end(&msg->sg.data[msg->sg.end]); sk_mem_charge(sk, use); offset = 0; copied -= use; sk_msg_iter_next(msg, end); num_elems++; i++; } /* When zerocopy is mixed with sk_msg_*copy* operations we * may have a copybreak set in this case clear and prefer * zerocopy remainder when possible. */ msg->sg.copybreak = 0; msg->sg.curr = msg->sg.end; }out: /* Revert iov_iter updates, msg will need to use 'trim' later if it * also needs to be cleared. */ if (ret) iov_iter_revert(from, msg->sg.size - orig); return ret;}EXPORT_SYMBOL_GPL(sk_msg_zerocopy_from_iter); int sk_msg_memcopy_from_iter(struct sock *sk, struct iov_iter *from, struct sk_msg *msg, u32 bytes){ int ret = -ENOSPC, i = msg->sg.curr; u32 copy, buf_size, copied = 0; struct scatterlist *sge; void *to; do { sge = sk_msg_elem(msg, i); /* This is possible if a trim operation shrunk the buffer */ if (msg->sg.copybreak >= sge->length) { msg->sg.copybreak = 0; sk_msg_iter_var_next(i); if (i == msg->sg.end) break; sge = sk_msg_elem(msg, i); } buf_size = sge->length - msg->sg.copybreak; copy = (buf_size > bytes) ? bytes : buf_size; to = sg_virt(sge) + msg->sg.copybreak; msg->sg.copybreak += copy; if (sk->sk_route_caps & NETIF_F_NOCACHE_COPY) ret = copy_from_iter_nocache(to, copy, from); else ret = copy_from_iter(to, copy, from); if (ret != copy) { ret = -EFAULT; goto out; } bytes -= copy; copied += copy; if (!bytes) break; msg->sg.copybreak = 0; sk_msg_iter_var_next(i); } while (i != msg->sg.end);out: msg->sg.curr = i; return (ret < 0) ? ret : copied;}EXPORT_SYMBOL_GPL(sk_msg_memcopy_from_iter); /* Receive sk_msg from psock->ingress_msg to @msg. */int sk_msg_recvmsg(struct sock *sk, struct sk_psock *psock, struct msghdr *msg, int len, int flags){ struct iov_iter *iter = &msg->msg_iter; int peek = flags & MSG_PEEK; struct sk_msg *msg_rx; int i, copied = 0; msg_rx = sk_psock_peek_msg(psock); while (copied != len) { struct scatterlist *sge; if (unlikely(!msg_rx)) break; i = msg_rx->sg.start; do { struct page *page; int copy; sge = sk_msg_elem(msg_rx, i); copy = sge->length; page = sg_page(sge); if (copied + copy > len) copy = len - copied; if (copy) copy = copy_page_to_iter(page, sge->offset, copy, iter); if (!copy) { copied = copied ? copied : -EFAULT; goto out; } copied += copy; if (likely(!peek)) { sge->offset += copy; sge->length -= copy; if (!msg_rx->skb) { sk_mem_uncharge(sk, copy); atomic_sub(copy, &sk->sk_rmem_alloc); } msg_rx->sg.size -= copy; if (!sge->length) { sk_msg_iter_var_next(i); if (!msg_rx->skb) put_page(page); } } else { /* Lets not optimize peek case if copy_page_to_iter * didn't copy the entire length lets just break. */ if (copy != sge->length) goto out; sk_msg_iter_var_next(i); } if (copied == len) break; } while ((i != msg_rx->sg.end) && !sg_is_last(sge)); if (unlikely(peek)) { msg_rx = sk_psock_next_msg(psock, msg_rx); if (!msg_rx) break; continue; } msg_rx->sg.start = i; if (!sge->length && (i == msg_rx->sg.end || sg_is_last(sge))) { msg_rx = sk_psock_dequeue_msg(psock); kfree_sk_msg(msg_rx); } msg_rx = sk_psock_peek_msg(psock); }out: return copied;}EXPORT_SYMBOL_GPL(sk_msg_recvmsg); bool sk_msg_is_readable(struct sock *sk){ struct sk_psock *psock; bool empty = true; rcu_read_lock(); psock = sk_psock(sk); if (likely(psock)) empty = list_empty(&psock->ingress_msg);Lines 1–500 of 1261. 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// SPDX-License-Identifier: GPL-2.0 /* Copyright (c) 2017 - 2018 Covalent IO, Inc. http://covalent.io */ #include <linux/skmsg.h> #include <linux/skbuff.h> #include <linux/scatterlist.h> #include <net/sock.h> #include <net/tcp.h> #include <net/tls.h> #include <trace/events/sock.h> static bool sk_msg_try_coalesce_ok(struct sk_msg *msg, int elem_first_coalesce) { if (msg->sg.end > msg->sg.start && elem_first_coalesce < msg->sg.end) return true; if (msg->sg.end < msg->sg.start && (elem_first_coalesce > msg->sg.start || elem_first_coalesce < msg->sg.end)) return true; return false; } int sk_msg_alloc(struct sock *sk, struct sk_msg *msg, int len, int elem_first_coalesce) { struct page_frag *pfrag = sk_page_frag(sk); u32 osize = msg->sg.size; int ret = 0; len -= msg->sg.size; while (len > 0) { struct scatterlist *sge; u32 orig_offset; int use, i; if (!sk_page_frag_refill(sk, pfrag)) { ret = -ENOMEM; goto msg_trim; } orig_offset = pfrag->offset; use = min_t(int, len, pfrag->size - orig_offset); if (!sk_wmem_schedule(sk, use)) { ret = -ENOMEM; goto msg_trim; } i = msg->sg.end; sk_msg_iter_var_prev(i); sge = &msg->sg.data[i]; if (sk_msg_try_coalesce_ok(msg, elem_first_coalesce) && sg_page(sge) == pfrag->page && sge->offset + sge->length == orig_offset) { sge->length += use; } else { if (sk_msg_full(msg)) { ret = -ENOSPC; break; } sge = &msg->sg.data[msg->sg.end]; sg_unmark_end(sge); sg_set_page(sge, pfrag->page, use, orig_offset); get_page(pfrag->page); sk_msg_iter_next(msg, end); } sk_mem_charge(sk, use); msg->sg.size += use; pfrag->offset += use; len -= use; } return ret; msg_trim: sk_msg_trim(sk, msg, osize); return ret; } EXPORT_SYMBOL_GPL(sk_msg_alloc); int sk_msg_clone(struct sock *sk, struct sk_msg *dst, struct sk_msg *src, u32 off, u32 len) { int i = src->sg.start; struct scatterlist *sge = sk_msg_elem(src, i); struct scatterlist *sgd = NULL; u32 sge_len, sge_off; while (off) { if (sge->length > off) break; off -= sge->length; sk_msg_iter_var_next(i); if (i == src->sg.end && off) return -ENOSPC; sge = sk_msg_elem(src, i); } while (len) { sge_len = sge->length - off; if (sge_len > len) sge_len = len; if (dst->sg.end) sgd = sk_msg_elem(dst, dst->sg.end - 1); if (sgd && (sg_page(sge) == sg_page(sgd)) && (sg_virt(sge) + off == sg_virt(sgd) + sgd->length)) { sgd->length += sge_len; dst->sg.size += sge_len; } else if (!sk_msg_full(dst)) { sge_off = sge->offset + off; sk_msg_page_add(dst, sg_page(sge), sge_len, sge_off); } else { return -ENOSPC; } off = 0; len -= sge_len; sk_mem_charge(sk, sge_len); sk_msg_iter_var_next(i); if (i == src->sg.end && len) return -ENOSPC; sge = sk_msg_elem(src, i); } return 0; } EXPORT_SYMBOL_GPL(sk_msg_clone); void sk_msg_return_zero(struct sock *sk, struct sk_msg *msg, int bytes) { int i = msg->sg.start; do { struct scatterlist *sge = sk_msg_elem(msg, i); if (bytes < sge->length) { sge->length -= bytes; sge->offset += bytes; sk_mem_uncharge(sk, bytes); break; } sk_mem_uncharge(sk, sge->length); bytes -= sge->length; sge->length = 0; sge->offset = 0; sk_msg_iter_var_next(i); } while (bytes && i != msg->sg.end); msg->sg.start = i; } EXPORT_SYMBOL_GPL(sk_msg_return_zero); void sk_msg_return(struct sock *sk, struct sk_msg *msg, int bytes) { int i = msg->sg.start; do { struct scatterlist *sge = &msg->sg.data[i]; int uncharge = (bytes < sge->length) ? bytes : sge->length; sk_mem_uncharge(sk, uncharge); bytes -= uncharge; sk_msg_iter_var_next(i); } while (i != msg->sg.end); } EXPORT_SYMBOL_GPL(sk_msg_return); static int sk_msg_free_elem(struct sock *sk, struct sk_msg *msg, u32 i, bool charge) { struct scatterlist *sge = sk_msg_elem(msg, i); u32 len = sge->length; /* When the skb owns the memory we free it from consume_skb path. */ if (!msg->skb) { if (charge) sk_mem_uncharge(sk, len); put_page(sg_page(sge)); } memset(sge, 0, sizeof(*sge)); return len; } static int __sk_msg_free(struct sock *sk, struct sk_msg *msg, u32 i, bool charge) { struct scatterlist *sge = sk_msg_elem(msg, i); int freed = 0; while (msg->sg.size) { msg->sg.size -= sge->length; freed += sk_msg_free_elem(sk, msg, i, charge); sk_msg_iter_var_next(i); sk_msg_check_to_free(msg, i, msg->sg.size); sge = sk_msg_elem(msg, i); } consume_skb(msg->skb); sk_msg_init(msg); return freed; } int sk_msg_free_nocharge(struct sock *sk, struct sk_msg *msg) { return __sk_msg_free(sk, msg, msg->sg.start, false); } EXPORT_SYMBOL_GPL(sk_msg_free_nocharge); int sk_msg_free(struct sock *sk, struct sk_msg *msg) { return __sk_msg_free(sk, msg, msg->sg.start, true); } EXPORT_SYMBOL_GPL(sk_msg_free); static void __sk_msg_free_partial(struct sock *sk, struct sk_msg *msg, u32 bytes, bool charge) { struct scatterlist *sge; u32 i = msg->sg.start; while (bytes) { sge = sk_msg_elem(msg, i); if (!sge->length) break; if (bytes < sge->length) { if (charge) sk_mem_uncharge(sk, bytes); sge->length -= bytes; sge->offset += bytes; msg->sg.size -= bytes; break; } msg->sg.size -= sge->length; bytes -= sge->length; sk_msg_free_elem(sk, msg, i, charge); sk_msg_iter_var_next(i); sk_msg_check_to_free(msg, i, bytes); } msg->sg.start = i; } void sk_msg_free_partial(struct sock *sk, struct sk_msg *msg, u32 bytes) { __sk_msg_free_partial(sk, msg, bytes, true); } EXPORT_SYMBOL_GPL(sk_msg_free_partial); void sk_msg_free_partial_nocharge(struct sock *sk, struct sk_msg *msg, u32 bytes) { __sk_msg_free_partial(sk, msg, bytes, false); } void sk_msg_trim(struct sock *sk, struct sk_msg *msg, int len) { int trim = msg->sg.size - len; u32 i = msg->sg.end; if (trim <= 0) { WARN_ON(trim < 0); return; } sk_msg_iter_var_prev(i); msg->sg.size = len; while (msg->sg.data[i].length && trim >= msg->sg.data[i].length) { trim -= msg->sg.data[i].length; sk_msg_free_elem(sk, msg, i, true); sk_msg_iter_var_prev(i); if (!trim) goto out; } msg->sg.data[i].length -= trim; sk_mem_uncharge(sk, trim); /* Adjust copybreak if it falls into the trimmed part of last buf */ if (msg->sg.curr == i && msg->sg.copybreak > msg->sg.data[i].length) msg->sg.copybreak = msg->sg.data[i].length; out: sk_msg_iter_var_next(i); msg->sg.end = i; /* If we trim data a full sg elem before curr pointer update * copybreak and current so that any future copy operations * start at new copy location. * However trimmed data that has not yet been used in a copy op * does not require an update. */ if (!msg->sg.size) { msg->sg.curr = msg->sg.start; msg->sg.copybreak = 0; } else if (sk_msg_iter_dist(msg->sg.start, msg->sg.curr) >= sk_msg_iter_dist(msg->sg.start, msg->sg.end)) { sk_msg_iter_var_prev(i); msg->sg.curr = i; msg->sg.copybreak = msg->sg.data[i].length; } } EXPORT_SYMBOL_GPL(sk_msg_trim); int sk_msg_zerocopy_from_iter(struct sock *sk, struct iov_iter *from, struct sk_msg *msg, u32 bytes) { int i, maxpages, ret = 0, num_elems = sk_msg_elem_used(msg); const int to_max_pages = MAX_MSG_FRAGS; struct page *pages[MAX_MSG_FRAGS]; ssize_t orig, copied, use, offset; orig = msg->sg.size; while (bytes > 0) { i = 0; maxpages = to_max_pages - num_elems; if (maxpages == 0) { ret = -EFAULT; goto out; } copied = iov_iter_get_pages2(from, pages, bytes, maxpages, &offset); if (copied <= 0) { ret = -EFAULT; goto out; } bytes -= copied; msg->sg.size += copied; while (copied) { use = min_t(int, copied, PAGE_SIZE - offset); sg_set_page(&msg->sg.data[msg->sg.end], pages[i], use, offset); sg_unmark_end(&msg->sg.data[msg->sg.end]); sk_mem_charge(sk, use); offset = 0; copied -= use; sk_msg_iter_next(msg, end); num_elems++; i++; } /* When zerocopy is mixed with sk_msg_*copy* operations we * may have a copybreak set in this case clear and prefer * zerocopy remainder when possible. */ msg->sg.copybreak = 0; msg->sg.curr = msg->sg.end; } out: /* Revert iov_iter updates, msg will need to use 'trim' later if it * also needs to be cleared. */ if (ret) iov_iter_revert(from, msg->sg.size - orig); return ret; } EXPORT_SYMBOL_GPL(sk_msg_zerocopy_from_iter); int sk_msg_memcopy_from_iter(struct sock *sk, struct iov_iter *from, struct sk_msg *msg, u32 bytes) { int ret = -ENOSPC, i = msg->sg.curr; u32 copy, buf_size, copied = 0; struct scatterlist *sge; void *to; do { sge = sk_msg_elem(msg, i); /* This is possible if a trim operation shrunk the buffer */ if (msg->sg.copybreak >= sge->length) { msg->sg.copybreak = 0; sk_msg_iter_var_next(i); if (i == msg->sg.end) break; sge = sk_msg_elem(msg, i); } buf_size = sge->length - msg->sg.copybreak; copy = (buf_size > bytes) ? bytes : buf_size; to = sg_virt(sge) + msg->sg.copybreak; msg->sg.copybreak += copy; if (sk->sk_route_caps & NETIF_F_NOCACHE_COPY) ret = copy_from_iter_nocache(to, copy, from); else ret = copy_from_iter(to, copy, from); if (ret != copy) { ret = -EFAULT; goto out; } bytes -= copy; copied += copy; if (!bytes) break; msg->sg.copybreak = 0; sk_msg_iter_var_next(i); } while (i != msg->sg.end); out: msg->sg.curr = i; return (ret < 0) ? ret : copied; } EXPORT_SYMBOL_GPL(sk_msg_memcopy_from_iter); /* Receive sk_msg from psock->ingress_msg to @msg. */ int sk_msg_recvmsg(struct sock *sk, struct sk_psock *psock, struct msghdr *msg, int len, int flags) { struct iov_iter *iter = &msg->msg_iter; int peek = flags & MSG_PEEK; struct sk_msg *msg_rx; int i, copied = 0; msg_rx = sk_psock_peek_msg(psock); while (copied != len) { struct scatterlist *sge; if (unlikely(!msg_rx)) break; i = msg_rx->sg.start; do { struct page *page; int copy; sge = sk_msg_elem(msg_rx, i); copy = sge->length; page = sg_page(sge); if (copied + copy > len) copy = len - copied; if (copy) copy = copy_page_to_iter(page, sge->offset, copy, iter); if (!copy) { copied = copied ? copied : -EFAULT; goto out; } copied += copy; if (likely(!peek)) { sge->offset += copy; sge->length -= copy; if (!msg_rx->skb) { sk_mem_uncharge(sk, copy); atomic_sub(copy, &sk->sk_rmem_alloc); } msg_rx->sg.size -= copy; if (!sge->length) { sk_msg_iter_var_next(i); if (!msg_rx->skb) put_page(page); } } else { /* Lets not optimize peek case if copy_page_to_iter * didn't copy the entire length lets just break. */ if (copy != sge->length) goto out; sk_msg_iter_var_next(i); } if (copied == len) break; } while ((i != msg_rx->sg.end) && !sg_is_last(sge)); if (unlikely(peek)) { msg_rx = sk_psock_next_msg(psock, msg_rx); if (!msg_rx) break; continue; } msg_rx->sg.start = i; if (!sge->length && (i == msg_rx->sg.end || sg_is_last(sge))) { msg_rx = sk_psock_dequeue_msg(psock); kfree_sk_msg(msg_rx); } msg_rx = sk_psock_peek_msg(psock); } out: return copied; } EXPORT_SYMBOL_GPL(sk_msg_recvmsg); bool sk_msg_is_readable(struct sock *sk) { struct sk_psock *psock; bool empty = true; rcu_read_lock(); psock = sk_psock(sk); if (likely(psock)) empty = list_empty(&psock->ingress_msg);